The Effects of Transparent Outgoing Envelopes on the Response Rate and Speed in Mail Surveys

In this study, a mail survey was conducted in order to examine the effects of transparent envelopes (those allowing visualization of contents) on response rate and speed. The experiment was carried out by mailing a questionnaire covered with either transparent outgoing envelope or plain one to 1,000 households, whom were chosen by two-stage area sampling. As the result, the response speed of transparent envelopes was better than plain ones; however, there was little difference on response rates after sending follow-up postcards. This suggests that transparent envelopes, similar to follow-up mailing, may have a “reminder effect.”