<P> In psychology, the theory of planned behavior (abbreviated TPB) is a theory that links one's beliefs and behavior . </P> <P> The concept was proposed by Icek Ajzen to improve on the predictive power of the theory of reasoned action by including perceived behavioural control . It has been applied to studies of the relations among beliefs, attitudes, behavioral intentions and behaviors in various fields such as advertising, public relations, advertising campaigns and healthcare . </P> <P> The theory states that attitude toward behavior, subjective norms, and perceived behavioral control, together shape an individual's behavioral intentions and behaviors . </P>

What construct was added to the theory of reasoned action to create the theory of planned behavior