Promoting the return of lapsed blood donors: a seven-arm randomized controlled trial of the question-behavior effect

This study tested key variations in the question-behavior effect against a control condition or an implementation intention condition on returning to give blood among lapsed donors (individuals who had not given blood in the past 2 years).

At baseline, 7,000 lapsed donors were randomized to 1 of 6 experimental conditions or to a control condition. Participants in the experimental conditions were asked to complete a 6-item postal questionnaire assessing intentions only, interrogative intention, moral norm plus intention, anticipated regret plus intention, positive self-image plus intention, or implementation intentions. OBJECTIVE measures of behavior were obtained 6 and 15 months later. The frequency of registrations to give blood over the next 6 and 15 months was measured.

Intention-to-treat analysis of the frequency of registrations (GENMOD procedure, Poisson distribution) indicated main effects for condition (experimental vs. control) at both 6 months, χ²(1) = 4.64, p < .05, and 15 months, χ²(1) = 5.88, p < .05. Positive self-image and implementation intention interventions outperformed the control condition at 6 months. At 15 months, standard intention, interrogative intention, and regret plus intention conditions showed more frequent registrations compared with control and were just as effective as implementation intention formation. Moderation analysis showed that the moral norm and positive self-image conditions were significant for first-time (1 previous donation) but not repeat (2 or more previous donations) donors.

The question-behavior effect can be used to reinvigorate blood donation among lapsed donors, and can be as effective as forming implementation intentions.