<P> 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 produce the outcome . 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 refers to beliefs about the presence of factors that may facilitate or impede performance of the behavior . </P> <P> It is usually measured with items which begins with the stem, "I am sure I can...(e.g., exercise, quit smoking, etc .)" through a self - report instrument in their questionnaires . Namely, it tries to measure the confidence toward the probability, feasibility, or likelihood of executing given behavior . </P> <P> The theory of planned behavior specifies the nature of relationships between beliefs and attitudes . According to these models, people's evaluations of, or attitudes toward behavior are determined by their accessible beliefs about the behavior, where a belief is defined as the subjective probability that the behavior will produce a certain outcome . Specifically, the evaluation of each outcome contributes to the attitude in direct proportion to the person's subjective possibility that the behavior produces the outcome in question . </P> <P> Outcome expectancy was originated from the expectancy - value model . It is a variable - linking belief, attitude, opinion and expectation . The theory of planned behavior's positive evaluation of self - performance of the particular behavior is similar to the concept to perceived benefits, which refers to beliefs regarding the effectiveness of the proposed preventive behavior in reducing the vulnerability to the negative outcomes, whereas their negative evaluation of self - performance is similar to perceived barriers, which refers to evaluation of potential negative consequences that might result from the enactment of the espoused health behavior . </P>

Strengths and limitations of theory of planned behaviour