Page - 149 - in Applied Interdisciplinary Theory in Health Informatics - Knowledge Base for Practitioners

and theories of attitude, particularly the Theory of Propositional Control. It asserts that behavioural intention (the intention to engage in a behaviour) can be predicted by the person's attitude toward that behaviour and the subjective norm (perceived social pressure). Attitudes about performing an act are composed of beliefs about the consequences of the act, and the subjective evaluation of (or weight given to) these consequences. The model assumes, perhaps unwisely, that behavioural intention is strongly correlated with actual behaviour [7]. The Theory of Reasoned Action is probably best known in the field of health informatics for its influence on the development of the Technology Acceptance Model (TAM)[8], which asserts that the behavioural intention of using a particular technology is predicted mainly by the user's attitude toward the technology (Reasoned Action construct "attitude"), which is in turn predicted by perceived usability and usefulness2. The Theory of Reasoned Action was succeeded in 1985 by the Theory of Planned Behaviour, developed by Ajzen to improve the predictive accuracy of the model by adding perceived behavioural control (self-efficacy), again drawn from social cognitive theory, as a construct [9]. The authors note that perceived behavioural control can influence all of the other factors in the model, including actually performing the behaviour (i.e. the individual may intend to perform the behaviour, but ultimately does not do so because they feel they cannot.) The most recent version is the Reasoned Action Approach, an attempt to integrate the work of Fishbein, Ajzen, and several other models of behaviour change (Figure 2) [10]. It added beliefs about behaviour, norms, and control as formative constructs, and acknowledged the influence of external factors on shaping these beliefs. Like the Health Belief Model, the Reasoned Action family of models are limited to reasoned action, implicitly a conscious process. It also posits that intention leads directly to action. This is often not the case; people sometimes engage in behaviours without conscious choice (e.g. habits) and frequently do not engage in a behaviour despite good intentions. 2 See also Chapter 6, “Technology Acceptance Models in health informatics: TAM and UTAUT”. Figure 2: Reasoned Action Approach [10], showing constructs inherited from the Theory of Reasoned Action (white) and Theory of Planned Behaviour (light gray), as well as those new to the Reasoned Action Approach (dark gray). S.MedlockandJ.C.Wyatt /HealthBehaviourTheory inHealth Informatics 149