The Theory of Planned Behaviour (TPB) has received considerable attention in the literature. The present study is a quantitative integration and review of that research. From a database of 185 independent studies published up to the end of 1997, the TPB accounted for 27% and 39% of the variance in behaviour and intention, respectively. The perceived behavioural control (PBC) construct accounted for significant amounts of variance in intention and behaviour, independent of theory of reasoned action variables. When behaviour measures were self-reports, the TPB accounted for 11% more of the variance in behaviour than when behaviour measures were objective or observed (R2s = .31 and .21, respectively). Attitude, subjective norm and PBC account for significantly more of the variance in individuals' desires than intentions or self-predictions, but intentions and self-predictions were better predictors of behaviour. The subjective norm construct is generally found to be a weak predictor of intentions. This is partly attributable to a combination of poor measurement and the need for expansion of the normative component. The discussion focuses on ways in which current TPB research can be taken forward in the light of the present review.

This paper describes and reviews the theory of planned behavior (TPB). The focus is on evidence supporting the further extension of the TPB in various ways. Empirical and theoretical evidence to support the addition of 6 variables to the TPB is reviewed: belief salience measures, past behavior/habit, perceived behavioral control (PBC) vs. self‐efficacy, moral norms, self‐identity, and affective beliefs. In each case there appears to be growing empirical evidence to support their addition to the TPB and some understanding of the processes by which they may be related to other TPB variables, intentions, and behavior. Two avenues for expansion of the TPB are presented. First, the possibility of incorporating the TPB into a dual‐process model of attitude–behavior relationships is reviewed. Second, the expansion of the TPB to include consideration of the volitional processes determining how goal intentions may lead to goal achievement is discussed.

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The aims of the present study are fourfold: to apply the theory of planned behavior (TPB) to eating a low‐fat diet; to consider differences between self‐efficacy and perceived control over behavior (PCB); to examine self‐identity as a potential addition to the model; and to identify beliefs which may provide useful targets for interventions. Findings support the efficacy of the TPB as a predictor of low‐fat diet. Evidence for the distinction between self‐efficacy and PCB was provided by principal components analysis, patterns in prediction of intention, and the control beliefs associated with the two constructs. Self‐identity was found to independently predict intention and may prove a useful addition to the TPB. Finally, specific beliefs distinguished intenders from nonintenders, providing potential targets for health interventions. The findings are discussed in the context of previous TPB research and the need for multimethod assessments of behavior.

The theory of planned behaviour (TPB) has received considerable attention in the literature. However, there have been few attempts to assess the proposed causal links between beliefs, attitudes, intentions and behaviour. The present study was designed to assess the predictive validity and causal ordering of TPB constructs over a 3‐month period. Findings indicated good internal and test‐retest reliability of assessed components; evidence for a distinction between two processes of perceived behavioural control (self‐efficacy and perceived control); support for inclusion of self‐identity into the model; and predictive validity of the TPB over 3 months. Perhaps more importantly, there was some evidence to support causal ordering between predicted TPB variables. In particular, cross‐lagged panel correlation analysis supported the causal impact of self‐efficacy on intention. The present study supports the use of the TPB as a reliable predictor of intentions and behaviour over time. It also highlights the need for further research on the relationship between attitudes, perceived behavioural control and their underlying beliefs.

This study tested the ability of the theory of planned behavior to predict actual participation in physical activity and explored the development of activity habits in a 12-week longitudinal study. People enrolling in a gymnasium (N = 94) completed standard theory of planned behavior measures at baseline and follow-up; behavior was monitored objectively in the intervening period. The data were analyzed by using both standard and repeatable events survival analysis. Results showed that (a) perceived behavioral control was significantly predictive of intentions and actual behavior, (b) stable exercise habits developed in the first 5 weeks of the study, and (c) successful prior performance enhanced perceptions of behavioral control. The implications for developing theory-based interventions that promote the maintenance of health behavior are discussed.

This article reports two studies designed to test a theory of planned behavior‐based model of blood donation. In Study 1 (n= 136), self‐efficacy and self‐identity accounted for unique variance in behavioral intention. Study 2 (n= 172) extended Study 1: self‐efficacy, perceived control over behavior (PCB), self‐identity, and moral norm were all independently predictive of intention; behavioral intention predicted a proxy measure of behavioral enaction. Both studies provided evidence to support a distinction between self‐efficacy and PCB, and for the inclusion of self‐identity and moral norm into the model. Belief‐based measures discriminated intenders from nonintenders, and beliefs that accounted for unique variance in self‐efficacy and PCB were identified. The findings are discussed in relation to using models such as the theory of planned behavior to intervene in social and health behaviors.

This article reports two studies designed to test the hypotheses that lower levels of attitudinal ambivalence are associated with attitudes that are more predictive of behavior, more stable over time, and less pliable. Study 1 (n = 346) employed a prospective design to test the effects of ambivalence on attitude-intention-behavior relationships. Findings indicated that less ambivalent attitudes were more predictive of subsequent behavioral intentions and behavior but were unrelated to attitude stability. Study 2 (n = 344) used a simple pre-post experimental design and showed that ambivalent attitudes were more pliable in the face of a persuasive communication. The findings are discussed in relation to future research into the bidimensional conceptualization of attitudes.