The authors attempted to determine the effectiveness of abstinence education by comparing teen pregnancy rates, birth rates, and abortion rates for U.S. states for the year 2005 as a function of the degree to which each state emphasizes abstinence in its sex education programs. They do this by categorizing each state’s emphasis on abstinence education into four categories with zero being the least emphasis and three being the most emphasis.

Their statistical analysis found that teen pregnancy is positively correlated with abstinence education, and they conclude from this correlation that abstinence education is ineffective at reducing teen pregnancy and may increase it.

However, I am concerned that the authors draw too strong a conclusion of cause and effect from this correlation.

The federal government began promoting abstinence education in earnest in 1996 with the passage of Title V, Section 510 of the Personal Responsibility and Work Opportunity Reconciliation Act of 1996. Thus using 2005 data allowed sufficient time for abstinence education to yield observable effects. However the authors did not report a similar analysis for the available data prior to 1996.

I examined previous years using the authors’ laws and policy level categories from their Table 2 and teen pregnancy, birthrate, and abortion data from the same Guttmacher Institute report cited by the authors. State assignment to the categories would obviously change as curricula change over time, but keeping the categories the same allows a look at where each category was before Title V initiatives (assuming abstinence education was not taught in those states prior to 1996, which may not be true).

After reproducing the 2005 trends shown in Figures 1 and 2 I examined the years 1996 and 1988 and found that category 3 states have always had higher teen pregnancy and birth rates than category 0, 1, and 2 states. Thus it is not clear that Title V changes in sex education curricula are the cause of higher pregnancy rates for category 3 states.

I also plotted the change in teen pregnancy rates for the time spans of 1988 to 1996 (prior to Title V) and 1996 to 2005 (after Title V). Prior to Title V category 1 states had a significant decrease in teen pregnancy relative to all other states. After Title V category 1 states continued to show the largest change in teen pregnancy rate, but that change is not significantly different from change in category 3 states.

When data prior to Title V passage is considered it suggests that the correlation between abstinence education and teen pregnancy rates reported by the authors is not caused by changes in sex education curricula but something else.

Any such analysis has limitations, but in my opinion the
authors’ strong claim to cause and effect is not justified unless they can determine the effect of curriculum changes relative to a starting point prior to the change.