Role Identity and Reasoned Action in the Prediction of Repeated Behavior

In this study we compare predictions derivedfrom the theory of reasoned action and identity theory regarding intentions to give blood and blood donation behavior over a seven-month period. Using a sample of 658 blood donors stratified by number of donations, we found that the addition of measures of the importance of the blood donor role identity, of social relations connected to blood donation, and of habit significantly improved the prediction of intentions and donation over the levels provided by the Fishbein-Ajzen model. A developmental analysis suggested that the theory of reasoned action was most effective in predicting intentions and donation for first-time donors. Whereas the full augmented model was most applicable to long-term donors. The results were interpreted to mean that although the Fishbein-Ajzen model may be the most parsimonious model for the prediction of many non-role behaviors, it should be augmented with identity-theory variables for the prediction of established role behaviors.