The sixth in a series of eight reports on mental retardation in a Canadian province recorded in detail the research methodology used in acquisition of epidemiological data (incidence and disease control) and in depth knowledge of mental retardation as it occurred in the target population. In addition to attitudinal, demographic, and other variables, the procedure was explained to allow for raw and/or scaled scores for psychometric, and conceptual and social maturation. The project was designed to facilitate subsequent and more intensive analysis of test items and methodological variables. Eleven data cards were used, with the total number for each individual subject varying according to age and household status. Card types 01 and 02 referred to household data and card types 03 through 11 included individual subject data. Data for the 11 cards were included in the report. A glossary of terms and definitions concluded the work. Rationale for test and individual data was discussed in the other reports. (See also ED 040 528, ED 042 277, ED 038 787, ED 037 863, ED 047 472, EC 040 223, and EC 040 224.) (CB)