This theory builds on the Theory of Reasoned Action by adding a third determinant - perceived behavioural control. This component represents a person's beliefs about his or her ability to perform the behaviour in question.

This source claims that in the context of health behaviour, the Theory of Planned Behaviour can be expected to provide a better framework for understanding people's actions than the Theory of Reasoned Action. In particular, the model underscores the importance of assessing the extent to which target audiences possess the information needed to carry out a promoted action; the skills, resources and opportunities to act; and the support of other.