Different Response Rates in a Trial of Two Envelope Styles in Mail Survey Research

To determine whether academic physicians' response rates to a mail survey depend on the envelope used to mail the survey, we randomized 901 internists affiliated with a university department of medicine to receive a survey in either a university envelope or a Veteran Affairs envelope. The response rate among those receiving the Veterans Affairs envelope (41%) was 20% higher than the response rate among those receiving the university envelope (34%). We conclude that the packaging of a mail survey can influence the response rate.