Commercial coaching companies often report considerable gains in test scores by their clientele as proof of the effectiveness of their coaching programs. However, as Powers (1993) points out, variations in an individual’s test scores from one test administration to another can be expected to occur, and for a variety of reasons. First, test score gains may be the result of [-2-] a “practice effect”, wherein test takers have a greater sense of comfort, familiarity, and confidence when retaking a test (referred to by Bachman,1990, as “test-wiseness”) than they possessed in their initial experience with the same exam. Such changes may also reflect growth in an individuals ability over time, rather than the direct influence of test coaching programs. Furthermore, variations in scores – either increases or decreases – may be due simply to measurement error. Upon retesting, it is quite usual for some examinees to show large increases in scores, and for others to show large decreases. This phenomenon of regression to the mean was demonstrated in a study by Johnson et al. (1985) . Examining an SAT coaching program, it was noted that the gains or losses recorded by coached students varied greatly depending on their initial test scores. Students who scored lowest on their first encounter with the SAT tended to make the greatest gains upon retesting, while those who at first scored most highly were likely to make the smallest gains or largest drops in their second round scores.