This theory rests on the assumption that humans are reasonable animals who systematically process and use the information available to them in deciding what action to take. Thus, changing behavior is mainly a matter of changing the beliefs underlying the behavior. The theory suggests that effectively changing or reinforcing a given behavior in a given population requires a determination of whether that behavior is under attitudinal or normative control and of the crucial beliefs underlying the attitude or subjective norm. This research should take place before messages, educational programs, or community interventions are developed. For example, such information could be gathered from an elicitation study of 30 to 60 members of the population in question. The results of the elicitation study can then be used to develop a closed questionnaire for use in evaluating the effectiveness of the message or intervention. 7 references.