A randomized trial of opinion leader endorsement in a survey of orthopaedic surgeons: effect on primary response rates

BACKGROUND: Opinion leaders have been shown to have significant influence on the practice of health professionals and patient outcomes. METHODS: Using focus groups, key informants, and sampling to redundancy techniques, we developed a questionnaire of surgeons' preferences in the treatment of tibial shaft fractures. Twenty-two well-respected and widely known orthopaedic traumatologists endorsed the questionnaire. We randomized 395 surgeon members of the Orthopaedic Trauma Association to receive either a questionnaire that included a letter informing them of the opinion leaders' endorsement, or a questionnaire without the endorsement. RESULTS: Surgeons who received the letter of endorsement had a significantly lower response rate at 2, 4, and 8 weeks. The absolute difference in response rates was 7.8% (4.6% versus 12.4%, P < 0.05) at 2 weeks, 13.1% at 4 weeks (28.6% versus 41.7% P < 0.02), and 12.3% at 8 weeks (47.5% versus 59.8% P = 0.02). CONCLUSIONS: The addition of a letter listing expert surgeons who endorse the survey lead to significantly lower primary response rates. Those interested in influencing physician responses cannot always assume a positive effect from endorsement by opinion leaders