IMPROVING RESPONSE RATES THROUGH INCENTIVE AND FOLLOW-UP - THE EFFECTON A SURVEY OF PHYSICIANS KNOWLEDGE OF GENETICS

Objectives. This study assessed efforts to increase response rates to a mailed physician survey and examined whether, as a result, nonrespon se bias was reduced. Methods. Randomly selected physicians and genetic ists were mailed a questionnaire concerning genetics knowledge and att itudes. In the final but not the pilot survey, a $25 incentive and int ensive follow-up were used to increase the response rate. Results. The response rate from physicians in the final survey was 64.8% (n = 1140 ), compared with 19.6% in the pilot test (n = 69). Sample representati veness in sociodemographic and practice characteristics was improved b y follow-up. Respondents recruited with more difficulty did not differ on the principal outcome variable, genetics knowledge, except on one subscore. Pilot study and final survey respondents did not differ in k nowledge. Conclusions. Although the effect of increased response rates on the principal outcome variable in this study was minimal, this may not be the case for other studies. Every effort should be made to att ain as high a response rate as is practical and to establish that resp ondents are representative of the population being sampled.