This article reviews several decades of the author's meta-analytic and experimental research on the conditions under which nonrandomized experiments can approximate the results from randomized experiments (REs). Several studies make clear that we can expect accurate effect estimates from the regression discontinuity design, though its statistical…

Used meta-analyses to determine the effectiveness of behavioral marital therapy (BMT) and premarital intervention (BPI) studies. Found gains that were generally maintained over time, and equal for couples in Europe and the United States. Demonstrated higher effect sizes for comparisons of BMT with no treatment placebo control groups, whereas the…