Effect of hand versus electronic signatures on response rates in postal surveys: a randomised controlled trial among emergency physicians in Canada

OBJECTIVES: Hand signatures offer a more authentic personalisation, which carries over to a sense of trust, although are costly and time-consuming when considering large postal surveys. The objective of this study was to compare response rates when using either hand-signed or electronic-signed letters in a postal survey. DESIGN AND SETTING: We embedded this randomised controlled trial within a national cross-sectional postal survey of emergency physicians in Canada. The survey aimed to describe current practice patterns with respect to primary headache disorders. PARTICIPANTS: We randomly sampled 500 emergency physicians listed in the Scott’s Canadian Medical Directory, 2019 edition. INTERVENTIONS: Using computer-generated random numbers, physicians were allocated to receiving either hand-signed (n=250) or electronic signed (n=250) letters. The initial mailout contained a US$5 Tim Hortons coffee card with the invitation letter. Four reminders were sent to non-responders every 3 weeks. The same type of signature was used for the initial invitation and subsequent reminders. OUTCOME: The primary outcome was the survey response rate. RESULTS: Among 500 physicians invited, 32 invitations were undeliverable. Among the remaining 468 physicians, 231 had been allocated to the hand-signed group and 237 to the electronic signed group. The response rate in the hand-signed group was 87 (37.7%) vs 97 (40.9%) in the electronic-signed group (absolute difference in proportions −3.3%, 95% CI −12.1% to 5.6%). CONCLUSION: There was no significant difference in physician response rate between hand-signed and e-signed cover letter and reminder letters. Electronic signatures should be used in future postal surveys among physicians to save on time and labour without impacting response rates.