TRA was formulated in 1967 in an attempt to provide consistency in studies of the relationship between behaviour and attitudes (Fishbein & Ajzen 1975; Werner 2004). TPB (Ajzen 1991) is considered as an extension of TRA (Werner 2004). The main assumption of TRA and TPB is that individuals are rational in considering their actions and the implications of their actions (decision-making). Rational decision-making assumes that the decision is made under uncertainty (Basu 1996; Eppen et al. 1998). Rational decision-making implies that either optimum results were expected or the decision-making unit was aware of all the impacts and consequences (Basu 1996; Bazerman 2002; Eppen et al. 1998).
Figure 1. Theory of Reasoned Action (adopted from Fishbein & Ajzen 1975)
TRA was developed to examine the relationship between attitudes and behaviour (Ajzen 1988; Fishbein & Ajzen 1975; Werner 2004). There are two main concepts in TRA: “principles of compatibility” and the concept of “behavioural intention” (Ajzen 1988; Fishbein & Ajzen 1975). Principles of compatibility specify that in order to predict a specific behaviour directed to a specific target in a given context and time, specific attitudes that correspond to the specific target, time and context should be assessed (Ajzen 1988; Fishbein & Ajzen 1975). The concept of behaviour intention states that an individual’s motivation to engage in a behaviour is defined by the attitudes that influence the behaviour (Fishbein & Ajzen 1975). Behaviour intention indicates how much effort an individual would like to commit to perform such behaviour. Higher commitment is more likely to mean that behaviour would be performed.
Behaviour intention is determined by attitudes and subjective norms (Ajzen 1988; Fishbein & Ajzen 1975). An attitude refers to an individual’s perception (either favourable or unfavourable) toward specific behaviour (Werner 2004). ‘Subjective norm‘ refers to the individual’s subjective judgment regarding others’ preference and support for a behaviour (Werner 2004).
TRA was criticized for neglecting the importance of social factors that in real life could be a determinant for individual behaviour (Grandon & Peter P. Mykytyn 2004; Werner 2004). Social factors mean all the influences of the environment surrounding the individual (such as norms) which may influence the individual behaviour (Ajzen 1991). To overcome TRA’s weakness, Ajzen (1991) proposed an additional factor in determining individual behaviour in TPB (Figure 2), which is Perceived Behavioural Control. Perceived behavioural control is an individual perception on how easily a specific behaviour will be performed (Ajzen 1991). Perceived behavioural control might indirectly influence behaviour.
Figure 2. Theory of Planned Behavior (adopted from Ajzen 1991)
TRA and TPB have some limitations in predicting behaviour (Werner, 2004). The first limitation is that intention determinants are not limited to attitudes, subjective norms, and perceived behavioural control (Ajzen 1991). There may be other factors that influence behaviour. Empirical studies showed that only 40% of the variance of behaviour could be explained using TRA or TPB (Ajzen 1991; Werner 2004). The second limitation is that there may be a substantial gap of time between assessment of behaviour intention and the actual behaviour being assessed (Werner 2004). In that time gap, the intention of an individual might change. The third limitation is that both TRA and TPB are predictive models that predict an individual’s action based on certain criteria. However, individuals do not always behave as predicted by those criteria (Werner 2004).
In terms of IT adoption, TRA and TPB have been used to explain the adoption process from individual perspectives. TRA was modified into TAM to predict user acceptance of new computer technology (Chin & Marcolin 2001; Karahanna & Straub 1999; Legris, Ingham & Collerette 2003). TAM uses the same principles as TRA in predicting acceptance of IT (behaviour) from an individual’s intention to accept IT. The similarity has been assessed in a study involving 107 MBA students at the University of Michigan (Davis, Bagozzi & Warshaw 1989).
TPB has also been used to explain the adoption of IT. For example, TPB has been used to explain the adoption of voice-mail technology (Benham & Raymond 1996) and WAP service (Hung, Ku & Chang 2003). TPB is also comparable with TAM in explaining web presence in SMEs (Riemenschneider, Harrison & Mykytyn 2003).
Ajzen, I. 1988, Attitudes, Personality, and Behavior, Open University Press, Milton-Keynes.
Ajzen, I. 1991, ‘The Theory of Planned Behavior’, Organizational Behavior and Human Decision Processes, vol. 50, no. 2, pp. 179-211.
Basu, S. 1996, The Conceptual Difference Between Incomplete Information and Asymmetric Information: A Study of Business Behaviour in The Presence of Uncertainty, Macquarie University, Sydney.
Bazerman, M.H. 2002, Judgment in Managerial Decision Making, 5th edn, John Wiley & Sons, New York.
Benham, H.C. & Raymond, B.C. 1996, ‘Information Technology Adoption: Evidence from a Voice Mail Introduction’, Computer Personnel, vol. 17, no. 1, pp. 3-25.
Chin, W.W. & Marcolin, B.L. 2001, ‘The Future of Diffusion Research’, The Data Base for Advances in Information Systems, vol. 32, no. 3, pp. 7-12.
Davis, F.D., Bagozzi, R.P. & Warshaw, P.R. 1989, ‘User Acceptance of Computer Technology: A Comparison of Two Theoretical Models’, Management Science, vol. 35, no. 8, pp. 982-1003.
Eppen, G.D., Gould, F.J., Schmidt, C.P., Moore, J.H. & Weatherford, L.R. 1998, Introductory Management Science: Decision Modeling with Spreadsheets, 5th edn, Prentice Hall, Upper Saddle River.
Fishbein, M. & Ajzen, I. 1975, Belief, Attitude, Intention, and Behavior: An Introduction to Theory and Research, Addison-Wesley, Reading, MA.
Grandon, E.E. & Peter P. Mykytyn, J. 2004, ‘Theory-Based Instrumentation to Measure The Intention to Use Electronic Commerce in Small and Medium Sized Businesses’, The Journal of Computer Information Systems, vol. 44, no. 3, pp. 44-57.
Hung, S.-Y., Ku, C.-K. & Chang, C.-M. 2003, ‘Critical Factors of WAP Services Adoption: An Empirical Study’, Electronic Commerce Research and Application, vol. 2, no. 1, pp. 42-60.
Karahanna, E. & Straub, D.W. 1999, ‘The Psychological Origins of Perceived Usefulness and Ease-of-use’, Information & Management, vol. 35, no. 4, pp. 237-250.
Legris, P., Ingham, J. & Collerette, P. 2003, ‘Why Do People Use Information Technology? A Critical Review of The Technology Acceptance Model’, Information & Management, vol. 40, no. 3, pp. 191-204.
Riemenschneider, C.K., Harrison, D.A. & Mykytyn, P.P. 2003, ‘Understanding IT Adoption Decision in Small Business: Integrating Current Theories’, Information & Management, vol. 40, no. 4, pp. 269-285.
Werner, P. 2004, ‘Reasoned Action and Planned Behavior’, in S.J. Peterson & T.S. Bredow (eds), Middle range Theories: Application to Nursing Research, Lippincott Williams & Wilkins, Philadelphia, pp. 125-147.