Prestwood, J. Stephen2011-02-012011-02-011979Prestwood, J. Stephen. (1979). Knowledge of results and the proportion of positive feedback on tests of ability. Applied Psychological Measurement, 3, 155-160. doi:10.1177/014662167900300202doi:10.1177/014662167900300202https://hdl.handle.net/11299/99575Students were administered one of three conventional or one of three stradaptive vocabulary tests with or without knowledge of results (KR). The three tests of each type differed in the expected proportion of correct responses to the test items and thus in the expected proportion of positive feedback. Results indicated that the mean maximum- likelihood estimates of individuals’ abilities varied as a joint function of KR-provision and test difficulty. Students receiving KR scored highest on the most-difficult test and lowest on the least-difficult test; students receiving no KR scored highest on the least-difficult test and did most poorly on the most-difficult test. Although the students perceived the differences in test difficulty, there were no effects on mean student anxiety or motivation scores attributable to difficulty or proportion of positive feedback alone. Regardless of the proportion of positive feedback, students reacted very favorably to receiving KR, and its provision increased the mean level of reported motivation.enArticle