Estimates of Randomized Controlled Trials Across Six Areas of Childhood Intervention: A Bibliometric Analysis

Data on the frequency of experiments are elusive. One way to estimate how many experiments are done is by analyzing the contents of bibliographic databases. This article analyzes the citation information from six major bibliographic databases to estimate the proportion of randomized (or possibly randomized) experiments compared to all outcome or impact evaluation studies. The focus of the article is on the evaluation of programs designed for children (from birth to eighteen years of age). The results indicate that randomized studies are used in nearly 70 percent of childhood interventions in health care but probably in 6 to 15 percent of kindergarten through twelfth-grade interventions in education and juvenile justice. The article concludes with discussion about these data, particularly on suggestions of how to produce more outcome studies, and randomized experiments, of childhood interventions.