Technology Acceptance Model (TAM)

TECHNOLOGY ACCEPTANCE MODEL

Davis et al. (1989) originally formulated the Technology Acceptance Model (TAM) in an attempt to understand why people accept or reject information systems. Davis (1986) adapted Fishbein and Ajzen's (1980) Theory of Reasoned Action (TRA) to intentions to accept the information technology. The original TAM explained the causal links between beliefs (usefulness of an IS and ease of using the IS) and users' attitudes, intentions and “actual computer adoption behaviour”.  The purpose of the TAM was to explain and predict user acceptance of IS from measures taken after a brief period of interaction with the system.  Figure 1 shows the original TAM model. 

Figure 1: Original TAM Model 

A person's acceptance of an IS is hypothesized to be determined by his or her intention to accept it. The intention, in turn, is determined by the person's attitude toward the IS and his/her perceptions concerning its usefulness. Attitudes are formed from beliefs a person holds about the IS. The beliefs in the TAM consist of the targeted IS user's perceptions of its usefulness and its ease of use. External variables, such as the task, user characteristics, political influences, organizational factors, and the development process, are expected to influence technology acceptance behavior indirectly by affecting beliefs, attitudes, or intentions. The TAM intended to resolve the previous mixed and inconclusive research findings associating various beliefs and attitudes with IS acceptance. It had the potential to integrate various development, implementation, and usage research streams in IS.

Davis et al. (1989) empirically tested the original TAM and found that the data partially supported the model. In a post hoc data analysis combining the TRA and TAM, Davis et al. (1989) suggested a revision of the original TAM which they claimed was a “powerful [model] for predicting and explaining user behaviour based on only three theoretical constructs: intention, perceived usefulness, and perceived ease of use”.  The revised TAM proposed by Davis et al. (1989) is presented in figure 2.

Figure 2: Revised TAM Model 

The model has two versions: one concerning pre-implementation beliefs about usefulness and ease of use and the other involving post-implementation beliefs about usefulness and ease of use. The other notable difference between the original and revised TAM models is the lack of the attitude construct.  In addition to empirical findings (Davis et al. 1989, Adams et al. 1992) that support the notion of different models for pre- and post-implementation beliefs and acceptance, it is expected that beliefs or attitudes differ or change with experience.  The pre-implementation version of the TAM predicts the acceptance of technology with perceptions of usefulness and ease of use of the technology measured before its actual implementation. The post-implementation model uses perceptions of ease of use and usefulness as determinants of technology acceptance after implementation of the technology.

After a brief interactive introduction to an IS (the pre-implementation version), both the usefulness and ease of use beliefs are depicted as having a direct effect on intentions concerning the technology. In other words, an individual would rely on both their perceptions of usefulness and ease of use to form their intentions. These intentions then predict acceptance behaviour. After a period of actually using the IS (the post-implementation version), the ease of use belief is depicted as having an indirect effect on intentions.  The implication is that once individuals have been using an IS, their subsequent intentions are formed from their perceptions of its usefulness. Intentions then are expected to predict future technology acceptance behaviour.

Source: Szajna, Bernadette (1996), "Empirical Evaluation of the Revised Technology Acceptance Model", Management Science, 42 (1), pp. 85-92