Pledgers were not less sexually active than matched nonpledgers despite prepledge similarities on 128 factors. Past findings that pledgers were less sexually active than the general population of nonpledgers may be attributable to regression models' failure to adjust for vast prepledge differences between the groups. Our refined sample (both pledgers and matched nonpledgers) is more religious and sexually conservative than the general population of adolescents and would be predicted to delay sex without virginity pledges.18-21
Despite having had similar birth control attitudes 1 year before pledging, virginity pledgers were substantially less likely than matched nonpledgers to protect themselves against STDs and pregnancy, consistent with earlier studies.10,12
Virginity pledgers may be less likely to use condoms and contraception because many abstinence programs cause participants to develop negative attitudes about their effectiveness.7,41
More than 90% of abstinence funding does not require that curricula be scientifically accurate,6,9
and a 2004 review found incorrect information in 11 of 13 federally funded abstinence programs, primarily about birth control and condom effectiveness.42
Most virginity pledgers reported having had premarital vaginal and oral sex but did not seem to substitute oral and anal sex for vaginal sex, contrary to earlier studies.10
Virginity-pledge programs do not prepare pledgers to protect their health if they have sex, although most pledgers do have sex. Pledge programs have guidance for pledgers who initiate sex, such as the True Love Waits publication When True Love Doesn't Wait
the recommendations of which include a medical examination and a second, mentored pledge.
Virginity pledgers have 0.1 fewer past-year sexual partners on average, but this modest difference is unlikely to affect STD risk, because pledgers do not differ in the average number of lifetime partners (~3 each) or age of sexual initiation (age 21) or in empirical STD prevalence.
Few virginity pledgers continue to identify with their pledges 5 years after pledging, with >80% claiming to have never pledged, consistent with an earlier finding that half of pledgers disaffiliated within 1 year.38
This high rate of disaffiliation may imply that nearly all virginity pledgers view pledges as nonbinding.
Matching adjusts only for observed characteristics, but the finding of no difference is robust to matching adequacy. Even if unobserved differences remained after matching, the data could falsely indicate no difference between groups only if pledgers were less abstinent than nonpledgers. Differences between groups may be attributable to an unobserved characteristic, but large differences such as a 10 percentage-point difference in past-year condom use require finding unobserved characteristics with more effect than the 128 factors already matched on, which is unlikely.44
Outcome differences are biased toward showing a pledge effect, because the pledge is an intermediate variable to an unobserved treatment variable: abstinence education program participation, unmeasured in the Add Health survey. Approximately 5% of the 32 outcomes compared may be statistically significant by chance because of multiple comparisons. These biases are unlikely to cause a full 10 percentage-point difference at all levels of condom use.
Sexual behavior reports are likely biased toward showing a pledge effect because virginity pledgers may under-report sex38
; failure to observe a difference in sexual behavior reinforces the likelihood of no true difference.
Pledges were taken in 1996, but the prevalent pledge text and curriculum have not changed substantially since then, according to virginity pledge co-creator (Rev. James Hester, personal communication, September 20, 2007). Pledge programs differ in their educational programs, continued contact with pledgers, and possible effectiveness, but this study cannot differentiate among programs and computes an average difference over all programs.
Measurement is of self-reported virginity pledges, but within 1 year, half of the virginity pledgers denied having pledged.38
Adolescents who pledged and ended identification with the pledge before wave 2 were counted as nonpledgers, and 8.7% of wave 2 nonpledgers reported a pledge at wave 3; these bias results to show no pledge effect.
Adolescents were ≥15 years of age at wave 1 because of unavailability of sex and contraceptive attitude data for younger adolescents. Younger virginity pledgers may be more likely to delay sex over a period of 1 year, as a previous study found,12
but as was true for older adolescents, part of the delay is likely attributable to pledgers' prepledge attitudes, not the pledge.
Premarital sex, condom, and birth control use cannot be detected for married respondents and were not imputed. Anal and oral sex prevalence come from respondents' descriptions of each of their past relationships and, thus, are likely to be underestimates: 75% of respondents reported having had vaginal sex, but only 63.8% of respondents reported vaginal sex in describing past relationships.
This article maximizes internal validity, with sacrifice to external: the restricted subsample is not nationally representative.
The results suggest that the virginity pledge does not change sexual behavior. One cannot make causal inferences given the pledge's voluntary nature, but if the pledge decreased sexual activity, we would expect to observe a difference between virginity pledgers and comparable nonpledgers; indeed, this estimate is biased in favor of showing a pledge effect.
Given this evidence that pledgers are less likely than comparable nonpledgers to use condoms and birth control, and previous evidence that AOSE programs do not affect sexual behavior,7,8
federal AOSE funds should be shifted to evidence-based sex education programs that teach birth control and have been demonstrated to delay sexual initiation3,4
and increase safer sex practices.1,3-5
Virginity pledges are not a marker for less sexual activity and should not be used as a measure of abstinence sex education program effectiveness.