LifeSkills Training (LST)

Study 1

Summary

Botvin et al. (1990, 1995, 2000) and Griffin et al. (2004, 2006) conducted a cluster randomized trial to examine 56 New York State schools with 5,954 seventh-grade student participants. The schools were assigned to two LST groups (one with in-person training and one with video training) and a control group. Students in the schools were followed through 10 years to assess self-reported substance use and HIV risk behaviors.

Botvin et al. (1990, 1995, 2000) and Griffin et al. (2004, 2006) found that, relative to the control group, the two intervention groups reported significantly lower

• Marijuana use at posttest
• Tobacco, alcohol, and marijuana use at the three-year follow-up
• Driving violations at the three-year follow-up
• Illicit drug use at the 3.5-year follow-up.
• HIV risk behaviors at the 10-year follow-up.

Evaluation Methodology

Design:

Recruitment: The study recruited 56 schools in three geographic areas of New York State that contained 5,954 seventh-grade students. Griffin et al. (2006) reported that 5,569 of the students completed the baseline assessment.

Assignment: The schools were randomized within strata based on the level of reported cigarette use to one of three conditions: (1) an intervention with a formal one-day training workshop and implementation feedback by project staff (n = 18), (2) an intervention with training provided by videotape and no implementation feedback (n = 16), and (3) a treatment-as-usual control group (n = 22). Botvin et al. (1995) reported the loss of one school after random assignment but before the study began. That, plus the intentional oversampling of control schools, contributed to the uneven number of schools across conditions.

Assessments/Attrition: Initial assessments in Botvin et al. (1990) occurred at baseline (fall 1985) and at the end of each year of the three-year intervention (year one at the end of 1985/86, year two at the end of 1986/87, and year three at the end of 1987/88). The year-three assessment served as the posttest. Botvin et al. (1990) reported that, of the original 5,954 students eligible for the study, 4,466 (75%) provided data at both the pretest and posttest.

The assessment six years after baseline or three years after posttest in Botvin et al. (1995) came at the end of grade 12. It included 3,597 (60.4%) of the original 5,954 students. Griffin et al. (2004) also examined data six years after baseline but reported a sample size of 2,042 (34%), which oddly is the same sample size as at the 10-year follow-up.

The 6.5-year assessment or 3.5-year follow-up in Botvin et al. (2000) came after the end of grade 12. The subsample included only 447 (7.5%) participants who completed a mail questionnaire related to illicit drug use.

The assessment 10 years after baseline or seven years after posttest in Griffin et al. (2006) included 2,042 youth (34% of the students at baseline).

Sample: The initial sample was approximately half (52%) male and predominantly (91%) white. Participating students attended a mixture of suburban and rural schools, 83% lived with both parents, and 58% of the fathers attended at least one year of college. At the 10-year follow-up, participants had an average age of 25.

Measures: The measures came from student reports collected by research staff rather than the teachers who implemented the program or from mail or phone questionnaires. The exceptions are two measures based on records from the Department of Motor Vehicles.

At posttest (Botvin et al., 1990), the five behavioral outcomes included smoking frequency, drinking frequency, drinking amount, drunkenness, and marijuana use frequency. The study provided no information on the reliability or validity of the substance use variables. However, to enhance the validity of drug use self-reports, breath samples were collected at each data point. The breathalyzer data were not examined but were said to increase the validity of self-reports. Also, unique IDs helped ensure confidentiality. Other mediating outcome measures of knowledge, attitudes and beliefs, skills, self-efficacy, self-esteem, and social anxiety had, with two exceptions, acceptable alpha reliability values. A two-thirds subset of the sample was randomly selected to complete the mediating measures. 

At the three-year follow-up, Botvin et al. (1995) examined nine smoking, alcohol, and marijuana use measures and eight polydrug use measures based on the combination of tobacco, alcohol, and marijuana use. Students provided data through surveys completed in classrooms, by mail, or by phone. Although originally obtained as ordinal scales, the substance use outcomes were treated as dichotomies. The authors noted that carbon monoxide levels in expired air were significantly correlated with self-reported cigarette smoking (r = 0.35, p<.001) across groups, "providing presumptive evidence for the validity of the self-report data."

At the three-year follow-up, Griffin et al. (2004) matched student names to records at the Department of Motor Vehicles. Measures included two dichotomous scores - one indicating the presence of any violations on one's driving record and the other indicating the presence of any points.

At the 3.5-year follow-up, Botvin et al. (2000) examined eight outcomes measuring the frequency of lifetime use of illicit drugs. The measures summed individual items to create composite scores for marijuana, cocaine, inhalants, nonmedical pill use, heroin and other narcotics, hallucinogens, total illicit drug use, and total illicit drug use other than marijuana.

At the 10-year follow-up, Griffin et al. (2006) examined three measures of HIV risk behavior: number of sex partners in the last year, having sex when drunk or high, and high-risk substance use (i.e., alcohol or marijuana intoxication or use of other illicit substances). If participants reported all three, they received a score of one on the HIV risk index; otherwise, they received a zero.

Analysis:

The initial analysis (Botvin et al., 1990) used MANCOVA with pretest scores as covariates. Significant multivariate results were followed by univariate general linear models with preplanned comparisons of covariate-adjusted means. The models did not adjust for clustering within schools, the unit of assignment. More appropriately, given the cluster randomized assignment, the additional analysis reported in Footnote 3 used schools as the unit of analysis and thereby avoided the problem of inflated statistical significance.

The follow-up analysis (Botvin et al., 1995) treated schools as the unit of analysis. It employed ordinary least-squares regression for school means with baseline means, assignment blocks, and experimental groups as predictors. One-tailed significant tests were used, however.

Botvin et al. (2000) used generalized estimating equations to adjust for school clustering. The models controlled for gender, age, grades, and drinking frequency at baseline. Griffin et al. (2004, 2006) also used generalized estimating equations to adjust for school clustering.

Missing Data Strategy: Botvin et al. (1990, 1995, 2000) and Griffin et al. (2004, 2006) used complete cases without imputation of FIML.

Intent-to-Treat: Botvin et al. (1990) did not conduct an intent-to-treat analysis. They examined only the 3,684 students who received at least 60% of the prevention program. This high-fidelity sample included 82% of students with complete data and included 28 of the 34 randomized intervention schools but all 22 of the randomized control schools.

Botvin et al. (1995, 2000) and Griffin et al. (2004, 2006) conducted both intent-to-treat analyses using all participants with baseline and follow-up data as well as non-intent-to-treat analyses of participants experiencing high-fidelity implementation. Although using all available data, the intent-to-treat analyses were limited by very high attrition.

Outcomes

Implementation Fidelity:

The quantitative measure of the amount of intervention material covered ranged from a low of 27% to a high of 97% with a mean of 68%. The level of program implementation was roughly comparable for the two intervention conditions (67% and 68%). About 75% of the students in the prevention conditions were exposed to 60% or more of the program material.

Baseline Equivalence:

All reports used the analysis sample for tests of baseline equivalence.

• Botvin et al. (1990) reported that an overall MANOVA for the five primary behavioral outcomes at baseline showed no significant differences across the three conditions.
• Botvin et al (1995) tested for baseline equivalence of sociodemographic and outcome measures and reported that there were no significant differences.
• Botvin et al. (2000) reported that the conditions "were similar at baseline on most of the drug use variables, including smoking and drinking quantity, and drunkenness and marijuana use frequency." However, students in the control group reported significantly higher levels of drinking frequency than intervention students.
• Griffin et al. (2004) reported "no differences between the experimental and control groups at baseline in terms of gender composition or the alcohol use index."
• Griffin et al. (2006) reported no pretest differences "between the experimental and control groups in terms of any of the demographic variables (gender, minority status, or percent from two parent families), or in terms of rates of substance use or grades received in school in the 7th grade." Also, "there were no differences across conditions in terms of percent married or cohabitating, percent of college graduates, or percent with incomes of $15,000 per year or less."

Differential Attrition:

All reports tested for differential attrition by using the analysis samples for tests of baseline equivalence. In addition, each report included the following:

• Botvin et al. (1990) reported on a series of two-way ANOVAs for each of the primary behavioral outcomes. Main effects analyses found that baseline smokers, drinkers, and marijuana users had higher attrition rates than nonusers. Interaction effects analyses found greater attrition among the baseline marijuana users in the control condition. The authors thus noted that the net effect of the attrition was to provide for a more conservative test of the interventions. Otherwise, Botvin et al. (1990) reported that the demographic characteristics of the analysis samples "were the same as those of the original sample[s]."
• Attrition was high (40%) at the three-year follow-up (Botvin et al., 1995). With attrition as the outcome, the study tested for the main effects of condition and the interaction effects of condition and baseline drug use status. The authors reported that "No differential attrition effects were found for any of the drug use variables in either the full sample or the high fidelity sample."
• The attrition rate of 66% at the three-year follow-up in Griffin et al. (2004) was high, and the authors presented no tests other than the baseline equivalence comparisons.
• The attrition rate of 92.5% at the 3.5-year follow-up was exceedingly high (Botvin et al., 2000), but the authors presented no tests other than the baseline equivalence comparisons.
• The attrition rate of 66% at the seven-year follow-up was high (Griffin et al., 2006). The authors noted that the rate "was similar across conditions." Main effect analyses indicated that those who reported smoking, drinking, or marijuana use at baseline were significantly more likely to drop out of the study. Also, males and minorities dropped out of the study at a higher rate compared to females and non-minorities. However, interaction analysis indicated that the rate of attrition of substance users and demographic factors did not differ across experimental conditions.

Posttest:

Botvin et al. (1990) examined posttest results at the end of the three-year program. The individual-level MANCOVA analysis without adjustment for clustering found significant condition differences overall across the five substance use outcomes. Individual-level ANOVA tests then showed significant condition differences for three of the five outcomes: smoking, drunkenness, and marijuana use. The aggregate analysis reported in Footnote 3 accounted for clusters but used one-tailed tests for the three significant outcome variables. The one-tailed tests replicated the significant results for all three outcomes, but a two-tailed test showed only one significant outcome: marijuana use. Finally, 23 individual-level tests for risk and protective factors showed significant condition differences favoring the intervention groups (or 12 adjusting for multiple tests).

Long-Term:

At the six-year assessment or three-year follow-up, Botvin et al. (1995) reported 34 tests in Tables 2 and 3 (two conditions by nine substance use outcomes and eight polydrug use outcomes). Counting only those significant at .01 in the one-tailed tests, the results showed five significant outcomes. The intervention group without implementation feedback had significantly lower scores than the control group on monthly cigarette smoking, drunkenness, weekly poly cigarette and alcohol use, and weekly poly cigarette, alcohol, and marijuana use. The intervention group with implementation feedback had significantly lower scores than the control group on weekly poly cigarette, alcohol, and marijuana use.

Also, at six years, Griffin et al. (2004) found that, after controlling for 12th-grade alcohol use, the intervention group had lower odds of having driver's license violations (OR = .75) and lower odds of having driver's license points (OR = .75) than the control group. The authors noted that the effects remained significant without the control for alcohol use. Further tests suggested that stronger anti-drinking attitudes in 10th grade mediated the intervention effect on driver's license violations.

At the 6.5-year assessment or 3.5-year follow-up, four of eight tests reached statistical significance. The combined intervention groups relative to the control group had significantly lower use of heroin and other narcotics, hallucinogens, total illicit substances, and total illicit substances other than marijuana.

At the 10-year assessment or seven-year follow-up (Griffin et al., 2006), the intervention group had significantly lower HIV risk scores than the control group (OR = .70). However, the effect was not significant in estimates using structural equation models. Also, there was no intervention effect on condom use. Mediation tests suggested that the program reduced HIV risk behavior in young adulthood by reducing alcohol and marijuana intoxication during junior and senior high school, but the analysis used only a non-intent-to-treat high-fidelity sample.

Study 2

Study 3

Summary

Smith et al. (2004) and Vicary et al. (2004, 2006) used a cluster randomized trial to examine 732 seventh-grade students in nine Pennsylvania middle schools. The schools were randomly assigned to LST, infused LST that delivered the program as part of the regular curriculum, or a control group. Assessments through the end of ninth grade examined substance use outcomes.

Smith et al. (2004) found no effects of LST compared to the control group for males and found effects in grade seven for females that disappeared by grade eight. Vicary et al. (2004, 2006) found no effects on substance use in grades eight or nine.

Evaluation Methodology

Design:

Recruitment: The sample came from nine middle schools in nine rural Pennsylvania school districts. The schools were of low socioeconomic status (one third of the student body in the school district qualifying to receive free or reduced lunch) and had relatively small enrollment (less than 1,000). A total of 732 consented youths who began grade seven in 1999-2000 participated in the study.

Assignment: The cluster randomized design randomly assigned the nine middle schools to three conditions, each with three schools: LST (n = 234 students), infused LST that delivered the program as part of the regular curriculum (n = 297 students), and a control group that received neither program (n = 201 students).

Assessments/Attrition: The four assessments occurred at baseline (the beginning of grade seven) and the end of grades seven, eight, and nine. Students received the main program in grades seven and eight and received booster sessions in grade nine. Thus, all three of the post-baseline assessments occurred while the three-year LST program was ongoing. Smith et al. (2004) reported retention rates of 97% at baseline, 96% at the grade seven assessment, and 90% at the grade eight assessment. Vicary et al. (2006) reported that 79% of the students completed all four assessments.

Sample:

The sample was 54% male and 97% white.

Measures:

The six substance use outcome measures came from student self-reports and included frequency of cigarette use, alcohol use, drunkenness, binge drinking, marijuana use, and inhalant use. To maintain confidentiality, ID codes were used in place of names, and teachers were not present. However, 19 students were removed at the third assessment for suspicious or inconsistent answering patterns. Vicary et al. (2004) used log or double log transformations of these substance use variables to better approximate a normal distribution.

Vicary et al. (2004, 2006) examined numerous other self-reported risk and protective measures related to substance use, including attitudes, normative beliefs, knowledge, decision-making, communication skills, refusal skills, media awareness, assertiveness, and coping with anxiety. The scales all had good reliabilities.

Analysis:

The analysis used regression models with fixed effects for schools, controls for baseline outcomes and other covariates, and robust standard errors for non-normally distributed outcomes. There were too few schools to use multilevel models, but checks found "negligible" ICCs. The analysis also used multiple imputation with academic performance and religious participation serving as auxiliary predictors in the imputation model. The analysis did not examine main effects, as the authors stated that they made the decision a priori to analyze the outcomes separately for males and females.

Intent-to-Treat: The analysis used multiple imputation to include all participants.

Outcomes

Implementation Fidelity:

For the LST condition, the teachers delivered 90% of the lessons, and student attendance averaged 93%. The authors noted informally that program teachers would have benefitted from refresher training.

Baseline Equivalence:

Smith et al. (2004) noted condition differences for three variables (free lunch eligibility, substance use, and problem behavior) but gave no other details on the number of tests or the size of the differences. The models controlled for these three baseline measures. Vicary et al. (2004) stated that "Pre-intervention comparisons of the sample revealed no significant differences by treatment condition for any of the substance use variables or the variables used to construct risk status."

Differential Attrition:

Vicary et al. (2004) stated that completion rates for students were similar across the conditions (68% for LST versus 72% for the control group). Vicary et al. (2006) reported that there was "no differential attrition across the three conditions" but provided no details.

Posttest:

Seventh- and Eighth-Grade Results

Smith et al. (2004) presented separate results for males and females. For males, none of the 12 outcome tests (six at the seventh-grade assessment and six at the eighth-grade assessment) showed a significant difference in substance use between the LST group and the control group. For females, four of the outcomes at the end of seventh grade (alcohol use, binge drinking, marijuana use, and inhalant use) were significantly lower for the LST group than the control group, but all four differences declined to non-significance by the end of eighth grade.

Vicary et al. (2004) examined females only and presented separate results for low-risk and high-risk groups. Although the program significantly reduced substance use among both low-risk and high-risk girls at the end of grade seven, all the effects fell to non-significance by the end of grade eight. Tests for effects on the risk and protective factors showed a significant program effect at the end of grade eight only for knowledge among low-risk girls and assertiveness skills among high-risk girls. Overall, tests for moderation by risk status showed stronger treatment effects for the high-risk females than low-risk females.

Ninth-Grade Results

Vicary et al. (2006) presented separate analyses for females and males. They found no significant effects of LST relative to the control group for any of the substance use outcomes at the end of grade nine. For the risk and protective factors, they found that the LST groups did better than the control group on coping and communication for girls but found no effects for boys.

Long-Term:

Not examined.

Study 4

Summary

Botvin et al. (2001a, 2001b) and Griffin et al. (2003) used a cluster randomized trial to examine 29 New York City public schools with 5,222 seventh-grade student participants. The schools were assigned to an LST group or a control group that received the standard curriculum. Students in the schools were followed for two years to assess self-reported substance use.

Botvin et al. (2001a, 2001b) and Griffin et al. (2003) found that, relative to the control group, the LST group reported significantly lower

• Alcohol use and polydrug use at posttest,
• Tobacco use, alcohol use, and inhalant use at the one-year follow-up,
• Binge drinking at the two-year follow-up.

Evaluation Methodology

Design: Twenty-nine New York City public schools participated in the study. Schools were surveyed to determine the amount of cigarette use of students. The schools were then divided into high, medium or low use schools and randomized to either receive the LST intervention (16 schools) or be in the control group (13 schools). Students in the intervention condition received the 15 session LST curriculum in the 7th grade, and the 10 session booster curriculum in the 8th grade. Modifications to the standard LST curriculum were made to make the program more appropriate for the targeted population. These modifications included the inclusion of pictures of minority youth, appropriate language and behavioral rehearsal scenarios, and adjustment of the reading level. No changes were made that would affect the underlying prevention strategy of the lessons. The sessions were taught by the regular classroom teacher. Control youth received the standard curriculum in place in NYC schools.

Teachers who taught the program had attended a 1-day teacher training workshop. Trained observers randomly attended classes and completed observational forms to assess implementation fidelity in each year.

Sample: The sample consisted of a total of 5,222 seventh grade students. Demographic characteristics of the sample included approximately half (47%) male and predominantly minority (61% African-American, 22% Hispanic, 6% Asian, 6% White, and 5% other or mixed background). Sixty-two percent of participants were eligible for the free lunch program. Approximately half (53%) of students lived in dual-parent households and 36% lived in mother-only households. After the schools were randomized into groups, 69% of the sample (n=3,621) were in the treatment condition.

Measures: Participants were surveyed prior to treatment (pretest), 3 months after the first year of the intervention, and at one-year follow-up after the initial posttest at the end of the 8th grade. Students completed questionnaires of self-reported drug use behavior. Questionnaires were administered by a team of data collectors who were members of the same ethnic groups as participating students. Prior to implementation, breath samples (to measure carbon monoxide levels) were collected from all participants, in order to increase validity of self-report data collected. Two measures of cigarette smoking were conducted: frequency (9-item scale) and quantity (11-item scale). Two measures of alcohol consumption were conducted: frequency (9-item scale) and amount consumed per drinking occasion (6-item scale). Frequencies of smoking marijuana, getting "high" from marijuana, and using inhalants were also measured by using a 9-item scale. Polydrug use measures were based on the responses to single drug use frequencies and examined in terms of lifetime use and current use. Also included in the analysis of this study were assessments of behavioral intentions, drug attitudes and knowledge, and social and personal competence.

Analysis: Generalized linear models (GLM) ANCOVA were used to compare means of drug use between the conditions at posttest and follow-up. Since the intervention was administered at the school level, researchers also controlled for intra-cluster correlations (ICCs) among students within the schools by using generalized estimating equations (GEE) to adjust the estimated standard error. Regression analyses were conducted to determine the effects of mediating factors (knowledge, intention, normative expectations). Effects on binge drinking at the one- and two-year follow-up assessments were tested.

Outcomes

Baseline Equivalence and Differential Attrition: Pretest analyses indicated no significant differences between conditions for any of the substance-use variables. There were a few demographic differences between the groups in terms of race and proportion of students who received free lunch. These variables were controlled for in the regression analyses for program effects. Analyses conducted to determine differential attrition at posttest revealed that participants who reported substance use at pretest were more likely to not be included in the posttest measures. This resulted in a more conservative test of the program.

Fidelity Monitoring: The mean level of implementation fidelity was 48%, which suggests a lower level of fidelity than had been found in previous research.

Posttest: Posttest data were collected three months after intervention. Analysis revealed significant effects on each of the alcohol use measures (frequency, drunkenness, and drinking quantity) as well as lifetime polydrug use, compared with the control condition. When the ICCs were included in the more conservative GEE analysis, the p-value for drinking frequency became nonsignificant and polydrug use approached significance. Prevention effects included increased drinking knowledge, and normative expectations for smoking and drinking.

One-year: GLM analysis indicates significant effects after one year on measures of all drugs, tobacco (frequency and quantity), alcohol (frequency, getting drunk, quantity), and marijuana (frequency, getting high), as well as inhalant use, as compared to the control condition. When GEE analysis was conducted, p-values for both marijuana variables became nonsignificant, while all other variables retained significant effects.

One- and two-year effects on binge drinking: The prevention program had protective effects in terms of binge drinking at the 1-year (8th grade) and 2-year (9th grade) follow-up assessments. The proportion of binge drinkers was over 50% lower in the intervention group relative to the control group at the follow-up assessments. There were also several significant program effects on proximal drinking variables, including drinking knowledge, pro-drinking attitudes, and peer drinking norms.

High-Risk Subsample: Griffin et al. (2003) examined 21% of the original sample that was classified as high risk for substance use initiation based on having poor grades and peers who used substances (n = 802). Tests at one-year follow-up for the subsample controlled for pretest scores and used generalized estimating equations to adjust for school clustering. The text reported one-tailed probability levels but provided information to infer two-tailed significance levels. The (two-tailed) results showed that the LST group had significantly lower substance use means than the control group for smoking (d = .22), drinking (d = .22), and polydrug use (d = .21). In addition, the study reported no significant baseline differences between conditions and no differences across conditions in the determinants of attrition.

Study 5

Summary

Zollinger et al. (2003) used a quasi-experimental design to examine 16 Indiana middle schools, 12 of which self-selected to implement LST. Sixth-grade students (n = 1,598) were followed through eighth grade to assess cigarette use and attitudes and knowledge about cigarette use.

Zollinger et al. (2003) found that, relative to the control group, the LST group reported significantly lower

• Smoking prevalence
• Smoking knowledge and self-efficacy.

Evaluation Methodology

Design: Sixteen middle schools from the Indianapolis Public School (IPS) system were included in the study. The Life Skills Training curriculum was implemented in 12 of the 16 schools. Intervention schools were not randomly chosen, but the specifics surrounding their selection were not discussed in the study. Self-report surveys were administered by the IPS system in December of each study year (1997-2000) for all middle school students. The survey used a repeated panel design including those who were and those who were not exposed to the program. Survey administrators were instructed on guidelines and protocols for administering the survey, including issues regarding confidentiality, consistency, and logistics. Baseline data were collected in 1997 on sixth-grade students. In 1998, sixth- and seventh-grade students were surveyed, and in 1999 and 2000, sixth-, seventh-, and eighth-grade students in middle school were surveyed. Student identification numbers assigned by IPS were used to match the surveys completed by students in the sixth, seventh, and eighth grades. Two cohort groups were identified: those who participated in all of the 1997, 1998, and 1999 surveys, and those who participated in all of the 1998, 1999, and 2000 surveys. For this analysis, the two cohorts were combined (n = 1,598).

Responses to tobacco use items were used to classify students as frequent smokers, current smokers, those who tried smoking cigarettes, and non-smokers. Current smokers had smoked in the past 30 days. Non-smoking students had never smoked a cigarette, not even a puff or two. All other students were classified as having tried smoking.

Sample: Students enrolled in the IPS system from 1997-2000 (n = 27,865) were included in the study. About one-fourth (28.9%, n = 8,048) of students declined to participate or were not available when the survey was administered. A total of 610 surveys (2.2%) were excluded because students did not answer at least half of the questions, or staffing judged students did not complete the survey with true or serious responses. Average response rate used for analysis was 68.9% for the four surveys. A final total of 1,598 eighth-grade students completed the Youth Tobacco Survey while in the sixth, seventh, and eighth grades. Approximately 56% of the participants were female, 59% were African American, and 31% were White. Although the intervention schools were not randomly chosen, tobacco-related behavior and attitudes of these students at baseline did not differ significantly from nonintervention schools.

Measures: A self-administered survey collected data about middle school students' knowledge, attitudes, beliefs, self-efficacy, decision-making ability, and behavior toward tobacco use and related issues. Items for the survey instrument were derived from published instruments including the CDC Youth Risk Behavior Survey Questionnaire, 1993, CDC Behavioral Risk Factor Surveillance System Questionnaire, 1997, Health Survey for England-the Booklet for 13-15 year-olds, 1996, Alcohol and Other Drug Use Survey, Indiana Prevention Resource Center, 1995, Maryland Adolescent Survey, 1994, and Statewide Survey of Drug and Alcohol Use Among California Students, grades 7, 9, and 11, 1986. Other items were developed specifically for the survey.

Analysis: Completed surveys were compiled and verified. Responses were compared using the z -test for proportions to determine statistical significance. Results were presented for students with no exposure to the LST program (26.9%), exposure during one school year (32.9%), and exposure during two school years (40.2%).

Outcomes

Although survey data were collected annually from 1997-2000, no post-test analyses were conducted immediately after program implementation. Data was analyzed after the completion of the final round of data collection.

Smoking behaviors:

Current smokers: Overall, 12.5% of the participants were currently smoking, and 39.4% had tried smoking in the past. Roughly one-half (48.2%) had never tried smoking, not even a puff or two. Significantly fewer current smokers existed among those who completed the LST curriculum once (one year) or twice (two years) (10.5% and 10.3%) compared to those with no exposure (18.1%). There were significantly more non-smokers in the group exposed to LST at least one time. No differences existed between one and two exposures to LST in any of the smoking behavior categories. Significantly fewer White students exposed twice to the LST curriculum were currently smoking, compared to those not exposed. Significantly more students of both genders and racial groups exposed to LST indicated they did not hang out with friends who smoke cigarettes.

Tried smoking: No significant impact on students who had tried smoking.

Non-smokers: There were significantly more non-smokers with one or two years exposure to the program compared to those with no exposure. This was also true in the subgroups of males, females, and Whites.

Intentions to smoke: When non-smokers were asked about their intention to try smoking in the next 12 months, 83.7% indicated they would not do so. Significantly more males compared to females and more African American students compared to White students indicated they would not try smoking in the next 12 months. Significantly larger proportions of female students, White students, and all students exposed twice to the program indicated they did not think they would try smoking, compared to the no-exposure groups.

The program had no significant impact on quit-attempt rates among smokers.

Self-efficacy: Significantly more students exposed to LST indicated it would not be difficult to refuse an offer of a cigarette. Significantly more female students twice exposed to the curriculum reported it would not be difficult to say "no." Significantly fewer female students with more than one exposure to the program reported that their decision to smoke was affected by friends' smoking behaviors compared to students with no exposure. Significantly fewer African American students with exposure to the program were affected by their friends' smoking.

Attitudes: Significantly more students exposed to LST once or twice thought it was a good idea to pass laws against smoking in schools and other public buildings, compared to those with no exposure. More students in each gender group exposed to the curriculum thought it was a good idea to pass laws restricting smoking.

Knowledge: Although the vast majority (90%) of students knew cigarette smoking caused damage to the lungs, makes teeth look bad, and causes lung cancer and bad breath, significantly more students exposed to LST one or two times knew smoking caused damage to the heart, eyes, unborn babies, cancer of the mouth and lungs, strokes to the brain, and damage to the ears. These results were consistent across gender and racial variables.

Summary of effects: The LST curriculum positively impacted tobacco use and attitudes of IPS middle school students. Exposure to LST one or two times was associated with a reduction in the prevalence of youth smoking as well as positive shifts in self-efficacy, attitudes and knowledge. Most improvements occurred with one exposure, although some required two exposures.

Study 6

Summary

Botvin et al. (1997) used a cluster randomized trial to examine seven junior high schools in New York City with 833 student participants. The schools were assigned to an LST group or a control group that received the standard curriculum. Students in the schools were assessed on substance use at baseline and posttest.

Botvin et al. (1997) found that, relative to the control group, the LST group reported significantly lower

• Cigarette smoking at posttest
• Drinking at posttest
• Marijuana use at posttest
• Polydrug use at posttest.

Evaluation Methodology

Design: Seven junior high schools in New York City participated in the study. Assignment was at the school-level to either the Life Skills Training treatment condition or the standard care control condition. Treatment condition students received the 15-session Life Skills Training program. The program was revised to be more appropriate for the targeted population. Modifications included adjusting the reading level, illustrative examples, and suggested situations for behavioral exercises. Treatment teachers attended a one-day training workshop.

Sample Characteristics: There were 833 participating students at pretest. Of these, 721 (87%) also completed posttest measures. The majority of students were girls (53%) and the mean age of the students was 12.6 years. The ethnic-racial composition of the sample was 25.8% African-American, 69.6% Hispanic, .7% White, 1.4% Asian, 1.5% Native American, and 1.0% Other. Most of the sample lived with their mother-only (37.3%) or both parents (35%). The majority of students (78.6%) qualified for free or reduced lunch.

Measures: Measures were collected at pretest and at post-intervention (about three months after pretest). Students completed two measures: a questionnaire and a carbon monoxide (CO) breath sample to enhance the validity of the self-reported data. Students completed the questionnaire during class and answered questions about current drug use (5 behavioral measures: smoking, drinking, drinking amount, drunkenness, marijuana use; 2 multiple substance measures: ever use and current use) and intentions for drug use in the future. Also assessed were behavioral intention (for drug use), normative expectations, attitudes towards drug use, and social competence (decision making, advertising influences, anxiety reduction, and communication).

Analysis: General Linear Modeling was used for the analysis, and used only data provided by students who completed both the pre- and posttest. One-tailed significance tests were used. To examine the impact of mediating variables, ANCOVAs were used on measures of attitudes, normative expectations, and skills use.

Outcomes

Baseline Equivalence: Crosstabs were performed to determine pretest equivalence of the demographic variables by condition. There were no significant differences between conditions for gender, free lunch, or family structure. There were differences between conditions on race/ethnicity, with a lower proportion of Hispanic students and a higher proportion of African-American students in the control condition compared to the treatment condition. However, race/ethnicity was not related to any of the pretest drug use variables, meaning conditions were comparable at pretest.

Posttest: There were significant treatment effects found on all five individual drug use behavior variables and both multiple drug use measures, indicating that students in the treatment condition reported using all measured substances less often than students in the control condition. Significant treatment effects were also found on intentions to use for three of six measures (cigarettes, beer/wine, and marijuana). On the mediating variables, significant differences were found on all but one of the normative expectations variables, indicating that the intervention resulted in lower normative expectations for treatment students concerning various drugs, compared to students in the control group. Refusal assertiveness (under skills use measures) was also found to be a significant mediating variable.

Study 7

Summary

Botvin et al. (2006) used a cluster randomized trial to examine 41 New York City public and parochial schools with 4,858 sixth-grade student participants. The schools were randomly assigned to an LST group or a control group that received the standard curriculum. Students in the schools were assessed on measures of verbal and physical aggression, fighting, and delinquency at pretest and posttest.

Botvin et al. (2006) found that, relative to the control group, the LST group reported significantly lower

• Delinquency at posttest
• Frequent fighting at posttest.

Evaluation Methodology

Design: The sample consisted of 4,858 sixth grade students from 41 randomly assigned NYC public and parochial schools. There were 20 LST schools (n=2,374) and 21 control schools (n=2,484) who received the standard health eduction curriculum. Pretest assessment was in the sixth grade and posttest approximately three months later, after the LST students had received the first year of the curriculum.

Sample: The sample was 51% boys and 49% girls; 39% African American, 33% Hispanic, 10% White, 6% Asian, 2% Native American, and 10% of other or mixed ethnicity.

Measures: Measures assessed verbal and physical aggression, fighting, and delinquency.

Analysis: Analyses were run using generalized estimating equations to account for the within-cluster correlation. Pretest values of each outcome, plus gender, percent black, percent Hispanic, grades, and implementation score were used as covariates in the models.

Outcomes

Baseline Equivalence: The two conditions did not differ at baseline on any of the violence or delinquency scales, or on gender or academic performance. The intervention group had more Hispanic students (36.7%) than controls (30.2%), while the control group had more black students (43.8%) than the intervention group (33.1%).

Posttest Results:

In the full sample, the intervention reduced "any delinquency in the past year," "frequent fighting in the past year," and "frequent delinquency in the past year." Five other variables were not significantly different including past month and high frequency verbal and physical aggression, as well as fighting in the past year.

In the high fidelity sample, with students who received at least half of the LST intervention, there were significant prevention effects on Physical Aggression in the Past Month, Violence in the Past Year, and Delinquency in the Past Year. There were also significant effects for the high frequency of outcome behaviors (top quartile), including Frequent Verbal Aggression in the Past Month, Frequent Physical Aggression in the Past Month, Frequent Fighting in the Past Year, and Frequent Delinquency in the Past Year.

Study 8

Summary

Mackillop et al. (2006) used a pre-post design without a control group to examine two school districts in upstate New York that implemented LST.

Mackillop et al. (2006) examined change in schools implementing LST without a control group and found no significant improvement in substance use.

Evaluation Methodology

Design: An experimental pre- post-test design was used in this evaluation. Two school districts in suburban towns in Upstate New York were selected in an unspecified manner to implement LST to groups of 6th graders (approximately 11 years of age). The towns from which the school districts were drawn maintained populations of approximately 40,000 and 17,000, respectively, and were primarily Caucasian (92% in School District One and 96% in School District Two) with small percentages of ethnic minorities present. Prior to the study, parents of children enrolled in the sixth grade in participating districts were informed by letter that a new substance use prevention program was being implemented as part of the educational curriculum and would be evaluated on two occasions. Parents were given the option of refusing to allow their child to complete the assessments, but all children in classes where LST was implemented would receive the program as a part of the standard curriculum. No parents withdrew consent for their children to participate in the evaluation. The LST curriculum was delivered once per week for 15 weeks in School District One, while School District Two delivered the curriculum once per day in 15 consecutive class periods. In School District One, six students (7%) provided data for only one time point and were not included in the study; in School District Two, seven students (4%) provided data for only one time point and were not included in the study.

Sample: The sample for School District One was 55% male, 89% Caucasian, 4% African American, 0% Hispanic, 4% Native American, 1% Asian, and 0% Other. The sample for School District Two was 54% male, 83% Caucasian, 2% African American, 2% Hispanic, 9% Native American, 2% Asian, and 1% Other. An unusually large percentage of respondents indicated they were of Native American heritage, which is possible, but may also indicate a misunderstanding of the category Native American meaning "born in America."

Measures: The Life Skills Training Questionnaire (LSTQ) was used in both school districts. The LSTQ assesses a number of domains related to the LST program. The 90-item, 7 subscale Alcohol Expectancy Questionnaire-Adolescent Version (AEQ-A) was used to evaluate adolescents' outcome expectancies for drinking alcohol. Due to school district administrators' concerns, subscale 7, Sexual Enhancement, was not administered. The 36-item Self-Perception Profile for Children (SPPC) was used to measure perceived self-competence in children. Due to class period time constrictions, only one additional measure could be included with the LSTQ; therefore, students in School District One were administered the LSTQ and AEQ-A, while the students at School District Two were administered the LSTQ and the SPPC. Fidelity was assessed using two approaches. First, at the end of each lesson, teachers completed a Life Skills Training Implementation Checklist (LST-IC), a checklist for teachers and independent observers to assess two aspects of LST lesson adherence: objectives and topics/activities. Second, on 16 occasions independent observers rated fidelity using the LST-IC.

Analysis: Individual within subjects analyses of variance (ANOVAs) were conducted for each school district. In order to reduce skewness and kurtosis, in School District One inverse transformations were used on the pro-attitude toward substance use subscales and perceived peer substance use subscale, and a square root transformation was used on the second drug refusal skills subscale. In School District Two transformations were used in the substance use and intention to use scales. In both school districts, the substance use and intention to use scales were severely skewed due to low rates of substance use behavior, and transformations did not improve skewness. As a result, the data were recoded dichotomously and the McNemar test was used for these variables. For all variables, analyses included participants who provided valid pre-intervention and post-intervention data. Potential treatment-by-gender interactions were examined using 2 (male/female) X 2 (pre-test/post-test) mixed ANOVAs.

Outcomes

Implementation Fidelity: In School District One, the teacher presented the 15 LST lessons to six classes for a total of 90 class periods. A total of 48 of 90 (53%) LST-ICs were completed, which revealed that the mean proportion of objectives completed was 95% and that the mean topics/activities completed was also 95%. Six lessons were independently observed with the mean proportion of objectives completed rated at 99% and the mean proportion of topics/activities completed was rated at 100% by the independent observer. Mean student daily attendance was 94%.

In School District Two, the teacher also implemented LST for six classes and completed LST-ICs following all 90 lessons with a mean proportion of objectives completed of 93% and a mean proportion of topics/activities of 80%. Independent observation of 12 lessons resulted in a mean rating of 99% of objectives completed and 73% of topics/activities completed. Mean student daily attendance was 93%.

LST Outcomes:

School District One: At post-test there were statistically significant changes in the Overall Knowledge, Life Skills Knowledge, Drug Knowledge, Perceived Adult Substance Use, Pro-Smoking Attitudes, Pro-Drinking Attitudes, Assertiveness Skills, and Anxiety Reduction Skills subscales. All of these changes were in the hypothesized direction, reflecting positive prevention effects. The McNemar test revealed no changes in Use or Intention to Use from pre- to post-test for either specific substances or aggregate estimates.

School District Two: At post-test there were statistically significant changes on the Overall Knowledge, Life Skills Knowledge, Drug Knowledge, Assertiveness Skills, Self-control Skills, Perceived Adult Substance Use, and Perceived Peer Substance Use subscales. All changes were in the hypothesized direction, with two exceptions: A significant effect on the Perceived Peer Substance Use subscale reflected an increase in perceived prevalence and a significant effect on the Drug Refusal Skills II subscale reflected a decrease in self-reported drug refusal skills. As was the case for School District One, the McNemar tests detected no changes from pre- to post-test on the substance use or intention to use for either specific substances or aggregate estimates.

Effects by Gender: In School District One, no main effects or interactions were evident between gender and LST, with one exception: A main effect for anxiety reduction skills indicated that females generally reported greater anxiety reduction skills than males, regardless of the intervention. In School District Two, gender interaction effects were found on the Drug Knowledge subscale, with females learning more about drugs than males, and on the Anxiety Reduction Skills subscale, with females again exhibiting an improvement in anxiety reduction skills while males actually reported a decrease in self-reported anxiety skills. The analyses also revealed main effects of gender on the Overall Knowledge subscale and Life Skills Knowledge subscale, with both cases reflecting poorer performance in males.

Study 9

Summary

Spoth et al. (2002, 2006, 2008, 2008b, 2014) and Trudeau et al. (2003) used a cluster randomized trial that assigned 36 middle schools with 1,664 seventh-grade students to three conditions: LST, LST plus Strengthening Families 10-14, or a control group. Assessments of substance use continued through age 22.

Spoth et al. (2002, 2006, 2008, 2008b, 2014) and Trudeau et al. (2003) found that, relative to the control group, the LST group reported significantly

• Lower substance use initiation at 1.5 years after baseline
• Lower cigarette initiation at 5.5 years after baseline
• Slower growth rates in cigarette initiation and drunkenness at 5.5 years after baseline.

Evaluation Methodology

Design: Participants in the study were seventh graders enrolled in 36 randomly selected rural schools in 22 contiguous counties in a Midwestern state. Criteria for the selection of the initial pool of schools were: 20% or more of households in the school district within 185% of the federal poverty level; community size (school district enrollment under 1,200); and all middle-school grades (6-8) taught at one location. A randomized block design guided the assignment of the 36 schools to one of three experimental conditions: 1) a combined Life Skills Training (LST) and Strengthening Families Program 10-14 (SFP 10-14) group, 2) an LST only group, and 3) a no-treatment control group.

Students in the combined LST and SFP 10-14 group received both curricula, including booster sessions (n = 4 booster sessions for the SFP 10-14 and n = 5 booster sessions for LST), while students in the LST-only group received the LST curriculum including 5 booster sessions. For a detailed description of the SFP 10-14 program, see the complete write-up. After schools were matched and randomly assigned to conditions, school officials were contacted and informed of the experimental condition to which their school had been assigned. All seventh grade students in participating schools were recruited for participation. On average, 46 students in each school completed the pre-test (n = 1,664 total), with 549 in the combined LST and SFP 10-14 group, 621 in the LST-only group, and 494 in the control group. A total of 1,563 students completed the post-test (n = 517 in the combined LST and SFP 10-14 group, n = 583 in the LST- only group, and n = 463 in the control group), while 1,372 students completed the long-term follow-up (n = 453 in the LST and SFP 10-14 group, n = 503 in the LST only group, and n = 416 in the control group).

Trudeau et al. (2003) compared trends in outcomes between the LST-only and control groups. For this analysis, only students with no missing data and who had not changed schools were included. This resulted in a sample of 847 students in 24 schools and completion rates of 86-90% at the last assessment.

Data collection in the form of student surveys was completed in classrooms at pre-test, post-test (one month after completion of the intervention), and at the long-term follow-up (one year after completion of the intervention). In addition, a bogus pipeline procedure was performed in order to promote honesty in answering smoking related questions. The sample was analyzed for pre-test equivalence on sociodemographic and outcome measures; the only significant difference discovered was that the control group contained more dual-parent families than the two intervention groups. This variable was included as a control variable in the subsequent outcome analyses. Analysis of differential attrition revealed no significant dropout by condition interactions from pre- to post-test or from post-test to follow-up for any outcome or sociodemographic variable.

Spoth et al. (2014) presented results for 11 assessments overall, with four of the assessments coming after high school, at ages 19, 20, 21, and 22. The authors noted that their study eliminated 18 students "who changed conditions (i.e., moved from a school district in one condition into one in a different condition)." According to Figure 1, about 72% of the baseline students provided data at age 22. Of students eligible for the young adult follow-ups - those who participated in the 11th or 12th grade assessments - 84% provided data at age 22.  Overall, those who remained in the study had a lower level of substance use at pretest than those who dropped out. However, the authors reported only one instance of differential attrition: a lower rate of attrition among control group participants from dual biological parent families at the 19-year-old assessment point. "No other significant pretest or differential attrition effects were found" (p. 951).

Sample: Participants included all seventh grade students at these schools, who were recruited to participate. On average, 46 students per school participated in the pre-test, slightly over half (53%) were male, and the majority of participants (96%) were Caucasian. Analysis of the demographic characteristics of the groups at baseline revealed one difference: the control group contained more youth with dual-parent families, thus lowering their level of risk. This variable was included in the outcome analysis as a control variable. At post-test and follow-up, analyses were conducted to rule out differential attrition in the sample by examining Condition X Dropout Status interactions. No significant interactions were found at either follow-up, for any outcome or sociodemographic measure.

In a longitudinal analysis (Trudeau et al., 2003), the sample was limited to two conditions and students with no missing data across three time-points and who had not changed schools. The resulting sample was 52% male and 97% Caucasian. 77% were living with biological parents, and 21% qualified for free or reduced-price lunch.

Measures: Self-reported use of alcohol, cigarettes, marijuana, and medications not prescribed to the participant was obtained from the classroom-administered questionnaire. Individual items included (a) "Have you ever had a drink of alcohol?", (b) "Have you ever smoked a cigarette?", (c) "Have you ever smoked marijuana or hashish?", (d) "Have you ever used drugs or medications that were prescribed by a doctor to someone else?" All four items were answered using a yes/no format. Inconsistent reports in lifetime substance use were corrected. Lifetime use measures were adjusted to control for baseline use, with these adjusted lifetime use measures (new-user rates) indicating whether use was initiated since baseline. Three lifetime use items were individually examined and summed to form the substance initiation index (SII). Prior to implementation, breath samples (to measure carbon monoxide levels) were collected from all participants, in order to increase validity of self-report data collected.

Trudeau et al. (2003) also examined trends in three outcomes of interest. 1) Substance use expectancies were defined as negative attitudes towards substance use due to personal and social consequences. The variable was created by averaging five Likert-style attitudinal items (alpha = .85). 2) Refusal intentions measured students' expectation of refusing substances. The Likert-style items used for this variable came from two scales and had an alpha of .80. 3) Substance initiation measured whether students had already used alcohol, tobacco, and/or marijuana. Three dichotomous yes/no variables were summed to create an initiation scale. Since data were collected at three time-points, some answers were corrected for consistency. In other words, a student could not respond "no" if they had previously responded "yes."

Analysis: A multilevel (mixed model) analysis of covariance (ANCOVA) using SAS Proc Mixed with restricted maximum likelihood estimation and listwise deletion of missing data was used to test for intervention effects on the SII. Because assignment to treatment conditions was made at the school level, school was incorporated as a random effect in the analyses. In addition, new-user analyses for specific substances were conducted at the school level, based on the proportions of new users in each school. For the prescription drug misuse outcome (Spoth et al., 2008b), Fisher's exact test was used due to the small numbers of participants responding in the affirmative and lack of within-school dependence. The tests did not adjust for randomization of schools.

Trudeau et al. (2003) used latent growth and structural equation models to examine differences in trends between the LST-only and control conditions. Due to between-school variability and the need to adjust for within-school clustering, corrected standard errors and chi-square tests of model fit were calculated using restricted maximum likelihood estimation. The growth models incorporated baseline outcomes in the intercept and slope estimates. Consistent with an intent-to-treat analysis, the study used all students with data, although no attempt was made to follow students moving to other schools.

Spoth et al. (2014) used latent growth models with adjustments for clustering within schools and full information maximum likelihood estimation to include all available data. Rather than examining condition differences in outcomes during young adulthood, the models estimated the indirect effects of the interventions on substance use outcomes via adolescent initiation. That is, the intervention affected adolescent initiation of substance use, which in turn affected young adult substance use.

Outcomes

1.5 Years After Baseline (Spoth, Redmond, Trudeau, and Shin, 2002)

Because only initiation measures were applied in the outcome analysis, the post-test was considered to be the baseline time point (since the analyses examined differences in substance initiation after delivery of the interventions), and the pretest was delivered several months before the intervention was delivered. Results are reported at one year after the intervention posttest (1-1/2 years after baseline).

The substance initiation index (SII) score was lowest for the LST and SFP 10-14 combined condition, while the LST-only group had the next lowest SII score and the control group had the highest SII score. Adjusting for the one-tailed tests, the LST and SFP 10-14 combined group scored significantly lower on the SII than the control group, but the difference between the combined group and the LST only group was non-significant. The LST-only group was marginally significantly lower on the SII than the control group.

New User Rates: The LST and SFP 10-14 combined condition demonstrated the lowest new user rate for alcohol and marijuana compared to the LST only and control groups. The relative reduction rate (the percentage difference in the proportion of new users in the intervention group relative to the control group) for the combined condition was 30% for alcohol initiation, while the same rate for the LST only condition was 4.1%. There were no significant findings associated with cigarette initiation. With regard to the contrast of LST and the control group, marijuana new users was marginally significantly lower in the LST group, but the contrasts with new users of alcohol and cigarettes were not significant.

1.5 Year Trends (Trudeau, Spoth, Lillehoj, Redmond, & Wickrama, 2003)

Using data from three time-points (baseline, the end of the first year, and the end of the second year following booster lessons), researchers compared the LST-only and control groups in terms of their trends in three outcomes of interest. 1) The decline over time in negative expectancies towards substance was smaller for the treatment group than the control group, but the difference was marginally significant at p < 0.07. 2) Intention to refuse substances was also expected to decrease over time and the decrease was significantly (p < 0.01) smaller for the treatment than the control. 3) Substance use initiation was expected to increase over time, and the researchers found that this increase was significantly (p < 0.01) smaller for the treatment group than the control. Additional moderation tests found stronger intervention effects for girls than boys.

5.5 Years After Baseline (12th Grade Outcomes):

Spoth, Randall, Trudeau, Shin, Redmond, 2008

Using multilevel analysis of covariance (HLM with students nested within schools) with 428 12th grade LST-only students and 347 Control students, adjusting for the one-tailed tests, the index of substance use initiation (which includes alcohol, marijuana, and cigarette use) was significantly lower for LST-only vs. Controls. The growth trajectory was marginally significant. Examining the individual initiation measures showed that the LST-only group had significantly lower mean levels of cigarette initiation and marginally significant lower levels of marijuana initiation. The LST-only group also showed a significantly slower rate of increase across time for cigarette initiation and drunkenness initiation.

There were no significant effects found for either the 12th grade mean levels or for the growth trajectories for any of the more serious substance use outcomes (frequency of use, monthly poly-substance use, and advanced poly-substance use index). However, there were significant effects on all measures, with the exception of drunkenness frequency, for a higher-risk subgroup defined as those students who reported use of at least two of three substances (alcohol, cigarettes, and marijuana) at pretest.

11th and 12th Grade Methamphetamine Use (Spoth, Clair, Shin, Redmond, 2006): There was no significant difference in methamphetamine use between LST-only and control conditions at the 11th grade follow-up. At 5.5 years (12th grade), there was a significant difference between the LST-only and control groups in lifetime methamphetamine use. The LST + SFP group was lower in lifetime methamphetamine use at both 4.5 and 5.5 years, and in past year methamphetamine use at 4.5 years.

11th and 12th Grade Prescription Drug Misuse (Spoth, Trudeau, Shin, Redmond, 2008): There was no significant difference in prescription drug misuse between LST-only and control conditions at either the 11th or 12th grade follow-ups. The LST + SFP group was significantly lower in reported prescription drug misuse in the 11th grade, and this difference was marginally significant in the 12th grade.

9.5 Years After Baseline (Outcomes at Ages 19, 20, 21, and 22)

Spoth et al. (2014)

The latent growth models examined the indirect effects of LST versus the control group through adolescent initiation of substance use. The indirect effects produced lower levels in the LST group than the control group on four outcomes at ages 19-22: drunkenness frequency, alcohol-related problems during the past year, cigarette use frequency, and illicit drug use frequency. Only one of the outcomes, alcohol-related problems, showed an indirect effect of LST on the slope or rate of change, suggesting that the LST advantage declined over the young adult years. With controls for the indirect effects, LST had little direct influence on the outcomes. The results support arguments that the program influences adult substance use by delaying adolescent imitation, which then moderates substance use in young adulthood.

Study 10

Summary

Botvin & Eng (1980) and Botvin et al. (1980) used a cluster randomized trial to examine 281 students in grades 8-10 who were attending two New York City schools. The two schools were randomly assigned to an LST or control group. Student participants were assessed on smoking, smoking knowledge, and social relations at baseline, posttest, and three-month follow-up.

Botvin & Eng (1980) and Botvin et al. (1980) found that, relative to the control group, the LST group reported significantly

• Fewer smokers
• Higher smoking knowledge.

Evaluation Methodology

Design: A sample of 281 students was drawn from a population of eighth, ninth, and tenth grade science and health education students in two suburban New York City schools in an unspecified manner. Both schools (School A and School B) were generally comparable with respect to socioeconomic status and the prevalence of cigarette smoking and were predominantly middle class. The two schools were randomly assigned to either the experimental (n = 121) or the control (n = 160) condition. All participants were pre- and post-tested by questionnaire with respect to self-reported smoking status, smoking knowledge, psychosocial knowledge, locus of control, self-image, social anxiety, influenceability, and the need for group acceptance. Following the pre-test, students in the experimental condition participated in a 10-session smoking prevention program. Although sessions were conducted weekly, the time interval between the beginning and the end of the program was 12 weeks due to school holidays. The program was administered by an outside specialist and utilized a combination of group discussion and special skills training. Sessions included content on self-image, decision making, advertising techniques, coping with anxiety, communication skills, social skills, and assertiveness training. In addition to the material covered in each session, students were given outside assignments either to prepare them for specific sessions or to reinforce material already covered. All students participated in a Self-Improvement Project in which they worked over the course of the 10-week program toward improving some skill or toward changing some specific personal behavior. Self-improvement goals were broken down into a series of weekly subgoals in order to enable students to gradually shape their own behavior and to chart their weekly progress. Students in both groups completed two post-tests. The first post-test was administered at the completion of the smoking prevention program (12 weeks after the pre-test), and the second post-test was administered approximately three months later. Data for the three month post-test was collected on roughly 77% of the immediate post-test sample (80% for the experimental group and 74% for the control group).

Sample: No specific information regarding the gender or racial composition of the sample was provided.

Measures: The questionnaire consisted of 58-items (excluding basic demographic data) and was divided into 3 sections: questions relating to smoking behavior (10 items), knowledge questions (20 items), and questions designed to tap various psychological variables (28 items).

Analysis: All pre-test smokers were eliminated from the analysis of smoking status, permitting the comparison of the experimental and control groups in terms of the number of new smokers. A Chi-square analysis was performed to test between group differences in the number of new smokers in the experimental and control groups. A two-way analysis of variance (sex X treatment condition) was used to compare the between-group differences in knowledge and personality scores from pre- to post-test. These between-group comparisons were performed both for the total sample and for each of the three grade levels within the total sample.

Outcomes

Post-test: Botvin, Eng, and Williams, 1980
Significantly fewer students in the experimental group began smoking during the course of the study when compared to students in the control group. The LST smoking prevention program was not equally effective for all grade levels, however. LST was most effective (100%) in preventing the onset of smoking among eighth graders, less effective (75%) among the ninth graders, and the least effective (44%) among the tenth graders. Overall, the experimental group had a significantly greater increase in smoking knowledge than the control group, and there was a significant two-way interaction between sex and treatment condition for social anxiety, with the males in the experimental condition showing the greatest decrease in social anxiety.

Long-term: Botvin and Eng, 1980
At the three-month follow-up, there were still significantly fewer new smokers in the experimental group compared to the control group, although the percentage of students beginning to experiment with cigarettes increased between the immediate and three-month post-tests in both groups. For the eighth graders, there was a significantly greater decrease in the need for group acceptance among the students in the experimental group compared to the control group, with males in the experimental group showing the greatest decrease in social anxiety. For the ninth graders, there was a significantly greater increase in smoking knowledge among students in the experimental group than among the controls as well as a significantly greater decrease in the need for group acceptance. Among tenth graders, as with the eighth graders, there was a significant interaction between sex and treatment condition for social anxiety, with the males showing the greatest decrease.

Overall, the experimental group had a significantly greater increase in smoking knowledge between the immediate and three-month posttest than did the control group, with males in the experimental condition again showing the greatest decrease in social anxiety. Girls in the experimental group maintained a significantly greater decrease in identification with their peers. Among the eighth graders, the students in the experimental group had a significantly greater decrease in social anxiety compared to the control group. Similarly, there was a significantly greater decrease in the need for group acceptance and peer identification. For the ninth graders, the only significant difference between the experimental and control groups was where students in the experimental group had a greater decrease in the influenceability between the immediate and the three-month follow-up compared to the control group. Finally, among the tenth graders there was a significant two-way interaction between sex and condition for smoking knowledge.

Study 11

Summary

Aviles (2019) used a quasi-experimental design with propensity score matching to examine sixth-grade students in 13 schools that had implemented LST and 10 schools that had not. Self-reported substance use served as the outcome.

Aviles (2019) found that, relative to the control group, the LST group had significantly

• Fewer smokers.

Evaluation Methodology

Design:

Recruitment: The study examined sixth-grade students in 13 schools located in the mid-Atlantic region that had implemented LST.

Assignment: The quasi-experimental design matched the 13 LST schools (n = 1,052 students) to 10 control schools not utilizing the treatment (n = 494 students). The propensity scores used to match the schools resulted from the following predictors: gender distribution, socioeconomic status (i.e., percentage of low income students in the school as reflected by the percentage of youth receiving free or reduced-price lunch), locality (e.g., urban, suburban, or rural), aggregated community risk factor scale scores for the school (e.g., perceived availability of drugs), aggregated family risk factor scale scores for the school (e.g., poor family management, parental attitudes favorable to substance use), and aggregated school-based risk factor scale scores for the school (e.g., poor academic performance).

Assessments/Attrition: The cross-sectional design did not include baseline data. It instead measured the outcomes in the fall of sixth grade, presumably while the program was ongoing.

Sample:

The student sample was 89% Caucasian with 52% females.

Measures:

Data came from the Pennsylvania Youth Survey, administered in the fall every two years to students in grade six. The survey included 11 self-reported substance use measures and 12 measures of risk and protective factors. To maintain reliability of the substance use measures, students who provided inconsistent answers or reported using a fake drug were treated as having missing data. Reliabilities for the scales were as low as .42 and .61.

Analysis:

The analysis used two-level random effects models with linear, Poisson, inflated Poisson, binomial, and negative binomial link functions. Low ICC values of .002 to .014 indicated little clustering.

Intent-to-Treat: The use of Full Information Maximum Likelihood estimation enabled all participants to be included in the analysis except those with missing data on the gender, race, or age covariates.

Outcomes

Implementation Fidelity:

Not examined.

Baseline Equivalence:

Not examined.

Differential Attrition:

Not examined.

Posttest:

Of the 11 substance use measures, two showed a significant effect. The program partly impacted 30-day cigarette use by significantly reducing whether a person smoked but not the amount a person smoked. The program also had a significant iatrogenic effect on lifetime prescription drug use. There were no significant effects on the 12 risk and protective measures. Tests for moderation suggested stronger effects for boys than girls.

Long-Term:

Not examined.

Study 12

Summary

Velasco et al. (2017) used a quasi-experimental design that examined 55 high schools in Italy that had already implemented or not implemented the LST program. The LST schools had 1,350 students, while the control schools with similar characteristics had 1,014 students. Student assessments of substance use came at baseline and posttest.

Velasco et al. (2017) found that, relative to the control group, the LST group reported significantly

• Lower rates of smoking initiation at posttest
• Greater substance use knowledge at posttest
• Less positive attitudes toward smoking at posttest
• Lower normative expectations about smoking and drinking at posttest.

Evaluation Methodology

Design:

Velasco et al. (2017) conducted a quasi-experimental design with crude matching that involved 55 schools in the Lombardy region of Italy. Data were collected before (baseline) and after (posttest) implementation, and again one- and two-years following program completion.

Assignment:

All students who participated in the study were enrolled in one of 55 high schools distributed across Italy (n=3,048 students, 138 classrooms). Thirty-one intervention schools (n = 1,350 students) were randomly selected from the set of schools participating in a larger implementation of the program in Italy after being stratified by geographic area. For the comparison group, schools with similar characteristics (e.g., municipality size, school size, and students' demographics) as the intervention schools were selected, resulting in twenty-four control schools (n=1,014 students). Within each treatment and control school, 3 classes (if available) were randomly selected to participate in the study. During the first year of middle school, students in the intervention schools received 15 sessions of the treatment followed by 10 booster sessions implemented during the second year of middle school and nine during the third year. All comparison schools were not involved in other drug prevention interventions.

Attrition:

A total of 1,586 students from 106 classes and 48 schools completed a posttest after the final year of program implementation (i.e., at the two-year follow-up after implementation of the 19 booster sessions), for an overall attrition rate of 48%, 23% and 13%, respectively.

Sample:

Students were 51% female for the intervention and comparison and students had a mean age of 11 years. The majority of students in the intervention (92%) and comparison (90%) were Italian.

Measures:

Three forms of substance use were assessed, smoking, alcohol use, and drunkenness, each of which were measured using a 9-point frequency response scale anchored by 1 (never) to 9 (more than once a day).

Thirteen measures assessing risk and protective factors were collected, including:

• Life skills - assertiveness (sample α = .73); social skills (sample α = .68); decision-making (sample α = .80); advertising resistance skills (sample α = .69); and anxiety reduction skills (sample α = .67).
• Psychosocial outcomes - students' distress (sample α = .81); well-being (sample α = .81); and risk-taking (sample α = .68).
• Beliefs about substance use - knowledge of the physiological effects of substance use (no alpha reported); beliefs about myths/misconceptions about drugs (no alpha reported); attitudes about smoking (sample α = .78) and alcohol (sample α = .74); normative expectations related to tobacco and alcohol use in terms of perceived prevalence of drug use among adults (no sample alpha).

Analysis:

Analyses reported here examined the effects of the intervention at the 2-year follow-up (i.e., after the booster sessions). While the text states that covariates included pretest scores, gender and age, Table 4 (which reports results after the two-year follow up when the full program was completed) states that the covariates included just gender and age. Thus, it was not clear whether analyses controlled for baseline pretests. Analyses used GEE to account for the clustering of students within schools. Scores on the behavioral measures (smoking, alcohol use, and drunkenness) were recorded to identify students who initiated alcohol or tobacco use (never vs. more than once in lifetime), and those who transitioned from less than weekly use to weekly use in order to verify the effectiveness of the program in preventing the initiation or the regular use of these substances.

Intent-to-Treat:

It appeared that students were analyzed according to the condition in which they were assigned, which is in line with intent-to-treat protocol. Students with missing data at the posttest and 2-year follow up were dropped from the analysis.

Outcomes

Implementation Fidelity:

Not reported.

Baseline Equivalence:

There were no significant baseline differences between groups in terms of school characteristics (municipality size and school size) and school-level demographics (gender, age, and nationality). There were also no school-level baseline differences in substance use (tobacco, alcohol or drunkenness). Baseline equivalence tests, however, were not conducted at the classroom- or student-level.

Differential Attrition:

Differential attrition tests (i.e., assessing the baseline and demographic differences between completers and attritors) were not conducted. There were no significant differences in attrition found between groups with regards to baseline outcomes (i.e., well-being or substance use), but these attrition-by-condition tests did not assess demographic variables.

Posttest:

At the two-year follow-up (when the program, including all 19 booster sessions, was completed), results showed that compared to control, treatment students self-reported:

• Lower rates of initiating smoking (behavioral outcome)
• Higher rates of skills awareness and anxiety reduction skills (R&P factor)
• Greater knowledge of the physiological effects of substance use (R&P factor)
• More accurate believes and fewer misconceptions about drugs (R&P factor)
• Less positive attitudes toward smoking (R&P factor)
• Lower normative expectations about adults' smoking and drinking (R&P factors).

Out of the 13 R&P measures, however there was one negative effect (i.e., at the posttest, lower assertive skills were reported in the treatment group compared to the control group).

Long-Term:

Not conducted.

Study 13

Summary

Crowley et al. (2014) used a quasi-experimental design with propensity score matching that examined seventh-grade students in 28 school districts across Iowa and Pennsylvania. Schools in the treatment districts but not the control districts implemented LST (or one of several other programs). Use of nonmedical prescription opioid use served as the outcome.

Crowley et al. (2014) found that, relative to students in the control group, students in the LST group reported significantly

• Lower use of nonmedical prescription opioids.

Evaluation Methodology

Design:

The National Institutes of Health funded an evaluation of the PROSPER model designed to disseminate a menu of evidence-based prevention interventions (EPBIs) that are both family- and school-based. Included in the menu of EPBIs were the Strengthening Families Program offered in 6^th grade; and All Stars, Life Skills Training and/or Project Alert school-based programs offered in 7^th grade. For the PROSPER evaluation, communities were randomly assigned to treatment (receiving the menu of EBPI's) or control (no menu of EBPI's). Crowley et al. (2014) conducted a multi-cohort quasi-experimental design utilizing propensity score matching to evaluate outcomes of students who received individual programs or some combination of school-based programs within the menu of EPBIs (treatment) compared to control. Self-report data assessing use of prescription opioids for nonmedical purposes were collected in 6^th grade (pretest) and at the end of each year through 12^th grade.

Recruitment:

From the 68 available school districts in Iowa and Pennsylvania where the PROSPER evaluation took place, 40 were excluded for not meeting the following eligibility requirements: (1) school district enrollment between 1301 and 5200 students, (2) at least 15% of families eligible for reduced cost lunch, (3) maximum of 50% of the adult population employed at or attending a college or university, and (4) the community could not be involved in other university-affiliated, youth-focused prevention initiatives. For the PROSPER evaluation, 28 school districts were matched by geographic location and size, and each pair of districts were randomized to condition (14 in the treatment and 14 in the control). The total number of individuals or families was not reported (just mean cluster sizes and cluster size ranges were reported). Within the treatment group, teams led by local cooperative extension agents and school officials selected a universal family and school program from one of the following evidenced based preventative interventions: 1) All Stars, 2) Life Skills, and 3) Project Alert. In addition, all families in the intervention group were offered the Strengthening Families Program for families with students in the 6th grade, but only some enrolled.

Assignment:

Which school-based evidence-based prevention interventions selected was determined within each of the 14 districts assigned to treatment, and families within the treatment group chose whether to attend the evening family program. Though not explicitly reported, it appeared that all 14 districts were involved in the quasi-experimental design reported by Crowley et al. (2014). In addition, a total of 5,026 students received one of the 3 school-based programs in 7^th grade, but it was not reported how many students (overall or by condition) were assigned to the treatment or control group. The propensity score model used to match control with treatment included 43 covariates covering four levels: individual, family, school, and research team. Examples of variables included: 18 student-level variables (prescription opioid use, gender, alcohol use, ever been intoxicated, level of alcohol use, inhalant use, hard drug use, tobacco use, youth substance use expectations, school attitude, problem solving capacity, school adjustment, school attendance, refusal efficacy, refusal intentions, stress management, substance use norms, and future use), 9 school-level variables (school uses a structured curriculum, percentage of free lunch, parent outreach, community pressure, teacher resistance, involvement of agency, school attitude towards prevention, district attitude towards prevention, and number of teachers in school), and 5 variables related to the research team (extension reputation, team size, time for parent recruitment, schools' prevention attitudes, and success of community coalition). These variables appeared to have been collected by surveys administered as part of the PROSPER evaluation.

Attrition:

No districts dropped from the sample, and n's at the student level were not reported (either at assignment or follow-up).

Sample:

50% of the students were female for the intervention and 51% for the treatment, and students had a mean age of 11.8 years overall. Students in the intervention and control groups had an average family income of $50,174 and $52,704, respectively. Around half of the sample in both treatment (50%) and control (53%) were from dual parent households.

Measures:

To evaluate youth nonmedical prescription opioid use, each participant was asked whether they had ever used prescription opioids for nonmedical purposes at the 6th grade pre-test and at the end of each school year through 12th grade.

Analysis:

A multi-step analytic framework was employed that included: (1) estimation of participants' propensity to receive different programs, (2) fitting marginal structural models to estimate the impact of receiving different programs on ever using prescription opioids for non-medical purposes, and (3) multi-level logistic models to account for clustering.

Intent-to-Treat:

It appeared that students were analyzed according to the condition in which they were assigned, which is in line with intent-to-treat protocol. Multiple imputation was utilized for missing data.

Outcomes

Implementation Fidelity:

Not reported.

Baseline Equivalence:

Not reported.

Differential Attrition:

Not reported.

Posttest:

There was no posttest result reported. Rather, results reflected findings across six years of data collection and showed that receipt of the Life Skills Training Program led to a significantly reduced probability of youth having ever used prescription opioids for nonmedical purposes by grade 12 compared to the control condition. No significant differences were observed between the All Stars and Project Alert Programs compared to control. Receipt of the Life Skills and family programs together as well as receipt of the All Stars and family programs together revealed a significant difference from the control condition in favor of the treatment group.

Long-Term:

Not conducted.