LABOR-SAVING STRATEGIES TO MAINTAIN SURVEY RESPONSE RATES - A RANDOMIZED TRIAL

To evaluate response-aiding strategies feasible in large surveys, we r andomly allocated general practitioners (GPs) to one of four intervent ion groups: Group 1 received 'exhaustive' telephone prompts by a medic al peer in advance of a questionnaire; Group 2, inclusion of an emboss ed pen with the questionnaire; Group 3, an advance letter prompt; and Group 4, a 'single attempt' advance telephone prompt by a non-medical research assistant. Follow-up procedures were identical. Response rate s by group were not significantly different overall (chi(2=)4.59, df=3 , p=0.20) although advance prompts by a medical peer were significantl y more effective than other strategies for male GPs. The difference in overall response rates between males (63%) and females (74%) was sign ificant (chi(2=)15.40, df=1, p<0.01). No other response bias was evide nt. Our demonstration of a significant interaction between respondent sex and response-aiding strategy invites further research.