Asking questions changes behavior: mere measurement effects on frequency of blood donation.

OBJECTIVE

This research examined the impact of completing a questionnaire about blood donation on subsequent donation behavior among a large sample of experienced blood donors.

DESIGN

Participants (N=4672) were randomly assigned to an experimental condition that received a postal questionnaire measuring cognitions about donation or a control condition that did not receive a questionnaire.

MAIN OUTCOME MEASURES

Number of registrations at blood drives and number of successful blood donations were assessed using objective records both 6 months and 12 months later.

RESULTS

Findings indicated that, compared to control participants, the mean frequency of number of registrations at blood drives among participants in the experimental group was 8.6% greater at 6 months (p<.0.007), and was 6.4% greater at 12 months (p<.035). Significant effects were also observed for successful blood donations at 6 months (p<.001) and 12 months (p<.004).

CONCLUSION

These findings provide the first evidence that the mere measurement is relevant to promoting consequential health behaviors. Implications of the research for intervention evaluation are discussed.