Variability in diagnostic procedures and a lack of valid and reliable measures led to the development of a comprehensive battery, which incorporated an operational definition of learning disabilities. The battery consisted of forms for observing these functions: intelligence, academic achievement, gross and fine motor control, visual perception, visual-motor coordination, auditory and verbal functioning, attention, and developmental history. It called for the administration of eleven standardized tests which measure these functions. Outdated norms, frequently for a limited age range, and questionable face validity indicated the need for restandardizing norms. Norms were obtained on 21 widely-used psychological tests from 540 children, ages 6.0 to 11.11, with controls for IQ, socioeconomic status, and sex. The data supported an expected relationship between visual and auditory-verbal cognitive functions, as well as between memory and attention span. Few sex differences were noted on the various subtests. Certain tests did not discriminate adequately at specific age levels because of limited range or wide variability of scores. Socioeconomic level was confirmed as an important variable, particularly when assessing auditory-verbal functions. Factor analysis was employed because of the large number of significant correlations among the tests. Three main factors indicating learning disability emerged: reasoning, auditory sequencing, and sound blending. (Author/CP)