The seventh in a series of eight reports on mental retardation in a Canadian province provided basic psychometric, social and conceptual maturity data of the study and outlined preliminary analytical tables designed to validate research questions. The report was explained to represent a transition from theoretical discussion of mental retardation to actual isolation and study of mentally retarded persons and other persons who had significant influence on lives of the retarded. Sections one through three placed individuals by age/sex categories on a table according to test scores on the Wechsler Intelligence Test for Children, the Draw-A-Person test, and the Vineland Social Maturity Scale. The psychometric data permitted selection of persons requiring further screening for mental retardation. Section four represented identification of sub-samples and significant persons groups. Demographical and analytical analysis in sections five and six tested variables related to epidemiology (incidence and disease control) of mental retardation as established in hypotheses included in the fourth report. The seventh section concerned interviewer evaluation. (See also ED 040 528, ED 042 277, ED 038 787, ED 037 863, ED 047 472, EC 040 222, and EC 040 224.) (CB)