The prediction of above-average participation in volunteerism: a test of the theory of planned behavior and the volunteers functions inventory in older Australian adults.

In the present prospective study of 81 older volunteers from a nonprofit organization in Australia, the authors compared the predictive utility of I. Ajzen's (1988) theory of planned behavior with that of E. G. Clary and M. Snyder's (1991) functional approach to volunteering. The authors mailed questionnaires to 385 volunteers in two waves of data collection. The first wave measured theory-of-planned-behavior variables and functional-approach variables. The second wave measured self-reported volunteering behavior for the previous month. Regression analyses supported both the theory of planned behavior and the functional approach; the theory of planned behavior accounted for a significantly larger proportion of variance in above-average participation in self-reported volunteerism. The findings of the present study provided some support for both the theory of planned behavior and the functional approach as models of self-reported volunteerism.