Questionnaire order significantly increased response to a postal survey sent to primary care physicians.

OBJECTIVE

Primary care physicians are increasingly being asked to participate in postal surveys. Difficulties in achieving adequate response rates among physicians have been reported. We investigated the effect of two low-cost interventions on response to a primary care physician postal questionnaire.

STUDY DESIGN AND SETTING

A 2x2 factorial trial was developed within the context of a national survey assessing views and practices of physicians regarding prostate-specific antigen testing. We evaluated questionnaire order (version 1: demographics first, version 2: topic-specific questions first) and written precontact. A national database of primary care physicians was compiled. One thousand five hundred ninety-nine physicians were randomly selected, stratified by health board, and randomized.

RESULTS

47.9% of eligible physicians completed a questionnaire. There was a statistically significant 5.1% higher response rate among physicians receiving version 1 of the questionnaire than those receiving version 2 (50.6% vs. 45.4%, P=0.05); the adjusted odds of response were significantly raised (odds ratio=1.24; 95% confidence interval=1.01-1.54). Precontact resulted in a nonsignificant 3.6% increase in response (49.8% vs. 46.2%; P=0.16). The interventions did not interact.

CONCLUSION

Ordering questionnaires with general questions first can significantly increase response rates, whereas precontact can achieve a modest increase. These strategies may enhance response while adding little to the cost of a physician survey.