The term learning disability was scarsely off the breath of the early pioneers when a profession began questioning its own integrity. Today, the proliferation of students classified as learning disabled (LD) has caused social, political, economic, and educational concerns that, in turn, have produced serious questioning of practices. The driving force behind most conceptualizations of learning disabilities is the discrepancy between ability and achievement; yet, the dimensions of this parameter have not been documented. The purpose of this investigation was to examine the nature and occurrence of discrepancies between ability and achievement scores of students demonstrating average overall performance on commonly used assessment devices. Ability and achievement scores in several domains on individual and group-administered tests were compared. In general, difference patterns of students with average overall performance scores were similar across grade levels and achievement tests. Average discrepancies were generally small; however, wide (30-50 points) ranges were evident at all grade levels for individual and group-administered tests. Implications of these findings for current and future use of discrepancies as estimators of disabilities are discussed.