School-based sex education curricula provide information about, and instruct students in, skills for sexual abstinence, Many programs also provide students information about birth control and ways to protect against sexually transmitted diseases (STD). We did not include programs that focused only on HIV or STD risk reduction because we focused on the prevention of teen pregnancy. We analyzed 14 studies of abstinence-only programs and comprehensive sexual health programs and found no significant differences (p=0.65) in effects on teens initiating sexual activity; only comprehensive programs measured pregnancy outcomes. Usually the programs lasted less than two months, however, a few were offered over two school years. Students were typically middle school- to early high school-age and most programs were led by teachers who received training in the curriculum. An exception was abstinence-only programs, which were usually offered by trained outside facilitators and trained student peer-leaders. Programs in our meta-analysis included Draw the Line/Respect the Line (Coyle 2004), Safer Choices (Coyle 2001), Reducing the Risk (Barth 1992), Sexual Health and Relationships (Henderson 2007), Promoting Health Among Teens comprehensive education (Jermmott 2010), Project Taking Charge (Jorgenson 1991), McMasters Teen Program (Mitchell-DiCenso 1997), Randomized Intervention Trial of Pupil Led Sex Education (Stephenson 2008), It’s Your Game: Keep It Real (Tortolero 2009), Managing Pressures Before Marriage (Blake 2001), For Keeps (Borawski 2005), Skills and Knowledge for AIDS and Pregnancy Prevention (Kirby 1997), and abstinence education (Treholm 2007).

 

Meta-analysis is a statistical method to combine the results from separate studies on a program, policy, or topic to estimate its effect on an outcome. WSIPP systematically evaluates all credible evaluations we can locate on each topic. The outcomes measured are the program impacts measured in the research literature (for example, impacts on crime or educational attainment). Treatment N represents the total number of individuals or units in the treatment group across the included studies.

An effect size (ES) is a standard metric that summarizes the degree to which a program or policy affects a measured outcome. If the effect size is positive, the outcome increases. If the effect size is negative, the outcome decreases. See Estimating Program Effects Using Effect Sizes for additional information on how we estimate effect sizes.

The effect size may be adjusted from the unadjusted effect size estimated in the meta-analysis. Historically, WSIPP adjusted effect sizes to some programs based on the methodological characteristics of the study. For programs reviewed in 2024 or later, we do not make additional adjustments, and we use the unadjusted effect size whenever we run a benefit-cost analysis.

Research shows the magnitude of effects may change over time. For those effect sizes, we estimate outcome-based adjustments, which we apply between the first time ES is estimated and the second time ES is estimated. More details about these adjustments can be found in our Technical Documentation.

Meta-Analysis of Program Effects
Outcomes measured	Treatment age	Primary or secondary participant	No. of effect sizes	Treatment N	Effect sizes (ES) and standard errors (SE)			Unadjusted effect size (random effects model)
					ES	SE	Age	ES	p-value
Teen pregnancy (under age 18) Becoming pregnant (or getting someone else pregnant) before age 18.	0	Primary	4	6130	0.121	0.080	17	0.102	0.029
Initiation of sexual activity Self-reported sexual intercourse.	0	Primary	8	5474	-0.024	0.064	15	-0.063	0.410

Barth, R.P., Leland, N., Kirby, D., & Fetro, J.V. (1992). Enhancing social and cognitive skills. In B. C. Miller, J. J. Card, R. L. Paikoff, & J. L. Peterson (Eds.), Preventing adolescent pregnancy: Model programs and evaluations (pp. 53-82). Thousand Oaks, CA: Sage.

Blake, S.M., Simkin, L., Ledsky, R., Perkins, C., & Calabrese, J.M. (2001). Effects of a parent-child communications intervention on young adolescents' risk for early onset of sexual intercourse. Family Planning Perspectives, 33(2), 52-61.

Borawski, E.A., Trapl, E.S., Lovegreen, L.D., Colabianchi, N., & Block, T. (2005). Effectiveness of abstinence-only intervention in middle school teens. American Journal of Health Behavior, 29(5), 423-434.

Coyle, K., Basen-Engquist, K., Kirby, D., Parcel, G., Banspach, S., Collins, J., . . . Harrist, R. (2001). Safer choices: Reducing teen pregnancy, HIV, and STDs. Public Health Reports, 116(Suppl. 1), 82-93.

Coyle, K.K., Kirby, D.B., Marin, B.V., Gomez, C.A., & Gregorich, S.E. (2004). Draw the line/respect the line: A randomized trial of a middle school intervention to reduce sexual risk behaviors. American Journal of Public Health, 94(5), 843-851.

Jemmott, J., Jemmott, L., & Fong, G. (2010). Efficacy of a theory-based abstinence-only intervention over 24 months: A randomized controlled trial with young adolescents. Archives of Pediatrics and Adolescent Medicine, 164(2), 152-159.

Jorgensen, S.R., Potts, V., & Camp, B. (1993). Project Taking Charge: Six-month follow-up of a pregnancy prevention program for early adolescents. Family Relations, 42(4), 401-406.

Kirby, D., Korpi, M., Adivi, C., & Weissman, J. (1997). An impact evaluation of project SNAPP: An AIDS and pregnancy prevention middle school program. AIDS Education and Prevention, 9(Suppl. 1), 44-61.

Mitchell-DiCenso, A., Thomas, B.H., Devlin, M.C., Goldsmith, C.H., Willan, A., Singer, J., . . . Hewson, S. (1997). Evaluation of an educational program to prevent adolescent pregnancy. Health Education & Behavior, 24(3), 300-312.

Stephenson, J., Strange, V., Allen, E., Copas, A., Johnson, A., Bonell, C., . . . the RIPPLE study team. (2008). The long-term effects of a peer- led sex education programme (RIPPLE): A cluster randomised trial in schools in England. PLoS Medicine, 5(11). doi: 10.1371/journal.pmed.0050224

Tortolero, S.R., Markham, C.M., Peskin, M.F., Shegog, R., Addy, R.C., Escobar-Chaves, S.L., & Baumler, E.R. (2009). It’s your game: Keep it real: Delaying sexual behavior with an effective middle school program. Journal of Adolescent Health, 46(2), 169-179.

Trenholm, C., Devaney, B., Fortson, K., Quay, K., Wheeler, J., & Clark, M. (2007). Impacts of four Title V, Section 510 abstinence education programs: Final report (Document No. PR07-07). Princeton, NJ: Mathematica Policy Research.