Fertility rates in the U.S. declined during the 1970's, both for teenages, 15-19, and all women, 15-44. Since the enactment of the Family Planning Services and Population Research Act in 1970 there have been large increases in both the number of family planning clinics in the U.S. and the number of women who receive their services. The aim of the Act was to give lowincome women access to effective contraception so that they could control their fertility and avoid unplanned births. The purpose of this study was to provide some evidence of the effectiveness of family planning programs in the U.S. as well as examine factors which influence family planning program enrollments.

The study used multivariate areal analysis to assess the independent effect of family planning program enrollment in 1978 on the fertility of these groups of women in 1980. Two models were used in the study to assess the relationship between program enrollment rates and fertility rates. The first was a cross-sectional model that examined the relationship in 1980 and addressed the question of whether areas with higher levels of enrollment had lower levels of fertility, other factors being equal. The second model, a lagged-dependent variable model, included the same variables as the cross-sectional model but also controlled for past fertility levels by including 1970 fertility rates as well as the effect of unmeasured factors related to fertility.