Kirby (2001) identified six quasi-experimental studies that assessed the impact of school-based health centers on the sexual behavior, contraceptive use, pregnancy rates, and birth rates of the school populations. These studies compared outcomes between schools that did and did not have clinics. None of the studies found an increase in sexual behavior as a result of school-based clinics. Findings were inconsistent for clinic impact on contraceptive use and birth rates, and none of the studies showed a significant impact on pregnancy rates. Kirby concluded that clinics that provided a clear message about both abstinence and contraceptive use and focused primarily on reproductive health had higher contraceptive use rates. However, in absence of experimental design, no concrete conclusions can be made about these types of programs.