The hypothesis of the JACM is that the five core job characteristics leads to three critical psychological states which in turn leads to improved motivation, satisfaction and performance. Also, job redesign affects performance through intrinsic motivation. Hickman and Lolled highlighted the need to address the mediating factor between job characteristics and outcomes is one’s psychological state.
The three psychological states in the redesign of jobs are employees’ need to experience work meaningfulness; experience personal work responsibility; and they must have knowledge of the results of their work activities. Additionally, JACM provides valuable guidelines for managers in terms of the specific characteristics of jobs that need to be taken into account when job redesign issues are being considered.
In particular, the theory suggested to managers the need for jobs to be diagnosed in terms of the extent to which they provided opportunities for task variety, task identity, task significance, autonomy and feedback (prescriptive value). Furthermore, by incorporating moderators (knowledge and skill, growth need strength and context satisfaction), the model consider the psychology of individual differences – the fact that different people in different situations may respond differently to attempts to redesign jobs.
As such, the theory represents a considerable step forward from the universalistic theory presented by Herbert, which assumed that job redesign would impact on everyone in the same way. If these moderators are present, job redesign will positively affect performance without the use of extrinsic rewards, as they moderate the strength of the impact of improvement in the five job characteristics on the three critical psychological states and its impact on the titivation and performance.
However, the five job characteristics of JACM are not exhaustive as there are other factors to job. Other limitations include JACM does not explain how jobs are redesigned (whether is it top down or participative); JACM does not take into account of organizational context, for instance, high skill as opposed to low and bureaucratic environments; and JACM focuses on a narrow range of outcomes, such as performance, motivation and satisfaction, which however exclude mental stress.