Comparison of open and closed questionnaire formats in obtaining demographic information from Canadian general internists

The objective of this study was to compare the impact of closed- versus ope n-ended question formats on the completeness and accuracy of demographic da ta collected in a mailed survey questionnaire. We surveyed general internis ts in five Canadian provinces to determine their career satisfaction. We ra ndomized respondents to receive versions of the questionnaire in which 16 d emographic questions were presented in a closed-ended or open-ended format. Two questions required respondents to make a relatively simple computation (ensuring that three or four categories of response added to 100%). The re sponse rate was 1007/1192 physicians (80.0%). The proportion of respondents with no missing data for all 16 questions was 44.7% for open-ended and 67. 0% for closed-ended formats (P < 0.001). The odds of having missing items r emained higher for open-ended response options after adjusting for a number of respondent characteristics (2.67, 95% confidence interval 2.01 to 3.55) . For the two questions requiring computations focused on professional acti vity and income, there were more missing data (P = 0.02, 0.02, respectively ) but fewer inaccurate responses (P = 0.009, 0.20, respectively) for the op en-ended compared to the closed-ended format. Investigators can achieve hig her response rates for demographic items using closed format response optio ns, hut at the risk of increasing inaccuracy in response to questions requi ring computation. (C) 1999 Elsevier Science Inc.