The authors have found little previous research related to gain scores on the TOEIC test and only two studies, Alderson & Wall (1993) and Alderson & Hamp-lyons (1996) concerning the TOEFL examination. These, however, were more concerned with the 'washback effect' on such test preparation on the actual content of classes and contained no objective data concerning the effects of coaching on subsequent test scores.
Fortunately, several studies have been conducted in relation to yet another standardized test, Educational Testing Service's SAT (Scholastic Aptitude Test), an exam which is administered to native-speaking high school students and is required as part of the application process for most American universities. Powers' (1993) "Coaching for the SAT: A Summary of the Summaries and an Update" is a thorough survey of such studies, particularly those which employ meta-analytical techniques to synthesize previous research. Much of what follows below has been drawn from this survey.