Patient education provides a vehicle for increasing the self-management of chronic illness and promoting modifications of life styles, which are considered important strategies for prevention. Evaluating the impact of such programs is complex and poses a number of methodologic and technical problems. Outcome measures of patient education programs are defined and reviewed in terms of the existing evaluation literature and our own studies utilizing diabetes as a prototype condition. Important dimensions of adaptation are outlined and indices to measure it discussed in an effort to examine aspects of educational programs directed at facilitating coping and maintaining quality of life. Factors which influence outcome variables are identified and include: patient factors (e.g., age, ethnic, socioeconomic, cultural, personality, and emotional), disease factors (e.g., severity of illness, age of onset, length of illness, mode of therapy), system factors (e.g., patient's location in the health care system, relation of teaching program to other health care providers). The effects of these factors are described including their implications for research design.