Definition (1):
Collective Effort Model is an interpretation of social loafing stating that perceived connections between individuals’ effort and their results are declining when they function together with others in a group.
Definition (2):
As per www.oxfordreference.com, Collective Effort Model is, “In psychology, a model proposing that working on tasks as part of a group tends to weaken individual motivation by (1) lowering the individual's expectancy that his or her actions can lead to the attainment of goals and (2) reducing the subjective value of these goals to the individual.”
Several social loafing models like evaluation potential, social impact, and dispensability of effort have been developed, but none are actually integrative models, and none considers more than a few conditions where loafing is decreased. Karau and Williams proposed the collective effort model (CEM) for filling this theoretical gap. The CEM states that social loafing is most comprehensively understood by mixing the expectancy theory’s motivational principles with self-evaluation theory’s principles. The focal point of the CEM is that individual effort and motivation in collective forms will be not affected provided that some contingencies are fulfilled or satisfied.