An attempt is made to clarify the language of the Adult Education Act of 1966 to yield operational criteria for identifying its goals within a needs assessment/treatment framework. Criteria for general and special target populations are set forth. Singled out are the group of those with four or less years of formal education and those determined to be the least educated and most in need (based on last grade completed, age, race/ethnicity, and economic status). Estimates of the sizes of Pennsylvania's target populations are made. Target and non-target populations are compared on the basis of sex, age, race, last grade attended, occupational group, major activity, and comparison of family income to poverty. In the second section target population trends, Adult Based Education (ABE) program participation, and ABE program demand and resource allocation are examined. Conclusions are presented based on the data: there has been an increase in the age and decrease in the size of Pennsylvania's ABE population, demand for ABE programs is about half that for all adult educational activities, and ABE program enrollment would probably increase were it not artificially controlled by the 20 per cent funding restriction for high school equivalency programs. The author contends that empirical criteria, information on data sources, and guidelines for target group identification should be developed at the federal level for use by the states. (MN)