Some research evidence supports aspects of the model (Roberts
& Glick, 1981); however, the model has also been criticized on several
grounds (Pinder, 1998). For example, the gen- eralizability of the model may be
limited by the fact that the research accompanying the development of the
model focused exclusively on pay as it relates to employee motivation.
Additional research is needed to test whether other consequences of
performance, both positive and negative (e.g., promotion, demotion, fatigue),
have the same impact on employees.
Also, Porter and Lawler tested their
propositions cross-sectionally rather than longitudinally, and this may result
in overestimates of the validity of the model (Taylor & Griess, 1976).
On the other hand, this model can provide managers with a useful
basis for analyzing and understanding motivational situations in organizational
settings. In addition, this model focuses on, and provides guidelines for, how
organizations can critically evaluate the effectiveness of their current
reward policies and practices.