perceived behavioral control, with each predictor weighted for its importance in relation to the behavior and population of interest. Behavior: an individual's observable response in a given situation with respect to a given target. Ajzen advanced the view that a behavior is a function of compatible intentions and perceptions of behavioral control. Perceived behavioral control is expected to moderate the effect of intention on behavior, such that a favorable intention produces the behavior only when perceived behavioral control is strong. Conceptual / operational comparison Perceived behavioral control vs. self-efficacy Ajzen (1991) wrote that the role of perceived behavioral control in the theory of planned behavior derived from Bandura's concept of self-efficacy. More recently, Fishbein and Cappella advanced the view that self-efficacy is equivalent to perceived behavioral control in Ajzen's integrative model. Perceived behavioral control can be assessed with the help of items from a self-efficacy scale. In previous studies, the construction of measures of perceived behavioral control has had to be tailored to each particular health-related behavior. For example, for smoking, an item could read "I don't think I am addicted because I can really just not smoke and not crave for it" or "It would be really easy for me to quit." The concept of self-efficacy is rooted in Bandura's social cognitive theory. It refers to the conviction that one can successfully execute the behavior required to attain a desired goal. The concept of self-efficacy is used as perceived behavioral control, which means the perception of the ease or difficulty of the particular behavior. It is linked to control beliefs, which refer to beliefs about the presence of factors that may facilitate or impede performance of the behavior. Perceived behavioral control is usually measured with self-report instruments comprising items that begin with the stem, "I am sure I can ... (e.g., exercise, quit smoking, etc.)." Such instruments attempt to measure the individual's confidence that he or she can execute a given behavior. Attitude toward behavior vs. outcome expectancy The theory of planned behavior specifies the nature of the relationship between beliefs and attitudes. According to the theory, an individual's evaluation of, or attitude toward, a behavior is determined by his or her accessible beliefs about the behavior. The term belief in this theory refers to the subjective probability that the behavior will produce a certain outcome. Specifically, the evaluation of each outcome contributes to the attitude commensurately with the