The relationship of test wiseness to I.Q. and the usability of I.Q. scores are discussed. Test wiseness involves the examinee's ability to obtain a high score on a standardized achievement test as a result of utilizing test-taking experience. Usability of I.Q. scores refers to the value of I.Q. scores to educators in making educational decisions. A primary reason for conducting the present investigation was to study the effects of repeated testing over an eighteen month interval. When I.Q. tests are administered over a short term, temporary sources of variance may be, at least in part, responsible for the increase in I.Q. Remembering specific items and practice effect provide plausible explanations for the short term gains. Gains found over periods of four months or less were not present over the longer time interval of eighteen months. (Author)