A study was made of nine reading tests, including both group and individually-administered measures, which are claimed to be chiefly diagnostic. Instruments analyzed were the following: Silent Reading Diagnostic Tests (Bond, Balow, and Hoyt), Botel Reading Inventory, Durrell Analysis of Reading Difficulty, Gates-McKillop Reading Diagnostic Tests, McCullough Word Analysis Tests, Roswell-Chall Diagnostic Reading Tests, Diagnostic Reading Scales (Spache), and Levels I and II of the Stanford Diagnostic Reading Test. Examination of the nine diagnostic batteries revealed subtests for (1) measuring potential reading level, (2) measuring silent and oral reading performance, (3) estimating reading levels, (4) identifying inhibiting factors, (5) determining chief skill deficiency area, (6) determining word identification technique, and (7) locating word recognition difficulties. Among the conclusions, it was stated that most instruments cannot be used to determine the chief area of skill deficiency, including specific problems of vocabulary, comprehension, and rate. Word recognition subtests are limited in scope of subskills assessed and emphasize spelling ability. In addition, skills for monosyllabic words are more often measured than skills required to unlock polysyllabic words. Group-administered tests are limited to silent activities. (WB)