The challenge
Policymakers wanted to reduce teen sex, pregnancy and sexually transmitted infections.
The case
From the late 1990s the US federal government funded school and community programs that taught abstaining from sex until marriage as the expected standard. Congress commissioned a rigorous evaluation of four programs, randomly assigning young people to take part or not. Years later, participants were no more likely to abstain than the control group, had sex at the same age and with the same number of partners, and were no less likely to have unprotected sex. At the final follow-up, 55 percent of control-group youth and 56 percent of program youth reported being abstinent over the previous 12 months, Mathematica found.
Why it didn't work
Programs designed around a moral message rather than evidence about what changes behavior had no effect. Comprehensive programs that include contraception information have stronger evidence.
Sources
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