The study involving 65 school psychologists, 38 special education teachers, and 21 "naive" university students (those not in education or psychology related programs) examined the extent to which school personnel were able to differentiate learning disabled (LD) students from low achievers by examining students' patterns of scores on psychometric measures. Each S was provided with forms containing information on 41 test or subtest scores of 9 school identified LD and 9 nonLD fourth grade students and was instructed to indicate which he/she believed were LD and which were nonLD. Accuracy and interjudge agreement confirmed the difficulty of differentially diagnosing students with learning disabilities and suggested that having information from a battery of tests does not increase the decision maker's ability to discriminate between LD and nonLD students. It was recommended that current assessment practices be simplified. (Author/SB)