The term "coaching" applies to a variety of types of test preparation programs which vary in length, instructional method, and content. Most research on the effectiveness of coaching has examined the Scholastic Aptitude Test (SAT), a measure of academic abilities used to predict college performance. This ERIC Digest reviews studies of coaching for the SAT and addresses the effectiveness of coaching. Of several studies reported between 1950 and 1967, the diversity in the research designs used, the types of coaching programs studied, and sample sizes make it difficult to compare results across studies in a meaningful way. In 1980, Slack and Porter synthesized many earlier studies on coaching, concluding that training can effectively help students raise their SAT scores. In 1978-1979, the Federal Trade Commission (FTC) studied the effect of commercial coaching on SAT scores. A 1981 synthesis of coaching studies by Messick and Jungeblut included most of the studies in Slack and Porter's report, plus the FTC results. The most recent synthesis included all those studies cited by Slack and Porter, and Messick and Jungeblut. It is concluded that the data support a positive effect of coaching, but the size of the effect estimated from the matched or randomized studies (10 points) seems too small to be practically important. Sixteen bibliographic citations are included. (LMO)