The relative efficacy of three interventions to favour return to give blood.

Background. The aim of the study was to test the relative efficacy of action planning and reward distribution to promote retention of whole blood donors. Materials and methods. A sample of 7,399 donors was randomised to one of three interventions: "action planning" (n=2,585); "reward" (n=2,397); and "thank you" (n=2,417). Participants in the action planning condition were invited to write the date of their next donation on a post-it note before taking it home at the end of the donation process. Participants in the "reward" condition were given an anti-theft credit card sleeve at the end of the donation process. The "thank you" intervention is the usual condition at the end of the process; it was considered the control condition. The dependent variable was the proportion of donors who registered to give blood at six months. Results. Overall, 4,444 (60.06%) donors registered to give blood at six months. There were no differences between the three interventions in the proportions of donors who registered to give blood (d.f. 2, chi-square=3.72, p<0.15). However, gender modified the effect of the intervention (d.f. 2, chi-square=6.57, p<0.0375); more women registered in the "thank you" condition than in the other two. Discussion. The results suggest that action planning and the distribution of a reward have no motivational effect on the return to give blood. Nonetheless, women appear to respond more negatively