The determinants of health promotive-behavior are proposed by Pender in the HPM. The exact impact of the various variables on singular behaviors or a lifestyle index, however, is far from conclusive. All the proposed factors have been supported through research, at least in part, as either directly or indirectly influencing the intent to participate in different health behaviors. The difficulty in concluding which variables are most critical is perhaps due to the variety of definitions, theoretical approaches (from different disciplines), and research methods. Of primary concern to this author is the overlap of activities among different "patterns" of behavior and the various definitions of such behavioral patterns. Little evidence exists on how specific types of behaviors relate to one another. Thus, knowing the determinants of a lifestyle index, for example, may be insignificant if the goal of nursing is to target priority behaviors that may indeed be influenced by more significant variables. For example, a person's perception of control may be a significant predictor of lifestyle behaviors in general; however, this variable may not impact on the person's decision to engage in changes related to exercise or activity behavior. Hence, because the motives behind various behaviors may be different, it seems more prudent to invest our research efforts on the impact of various factors on singular behaviors rather than lifestyle patterns. Finally, the efforts of nursing research on health behavior have been directed primarily at explaining the impact of various individual perceptions on the likelihood of behavior. Such focus has revealed some evidence of the significance of these variables, yet much unexplained variance remains. Perhaps it would be more prudent to direct attention at those variables such as situational or environmental factors that may impede or act as a cue to healthy behavior. Because the explanation of behavior has been individually focused (perhaps due to an "individualizing" theme in nursing education), the impact of the ecological model of behavior tends to be dismissed or underrated in nursing research. Knowledge of the impact of societal factors on behavior may be more appropriate to planning strategies for various groups rather than the behavioristic approaches that separate people from their social, physical, and economic environments. Thus, personal lifestyles may not be a simple matter of informed choice, and attention to the complex processes of societal opportunities, cultural interpretations, and group-specific attitudes must be studied further.