Response rates to postal questionnaires can be increased

Clinical question: 
How can response rates to postal questionnaires be increased?
Bottom line: 
Response rates to postal questionnaires can be increased by contacting people before they are sent the questionnaire. Questionnaires should be sent by first-class post or recorded delivery, and a stamped-return envelope provided. Questionnaires and letters should be maybe personal, and kept short. Incentives should be offered (preferably a small amount of money), and one or more reminders should be sent with a copy of the questionnaire to people who do not reply.
Caveat: 
The odds of response were reduced when the questionnaire included questions of a sensitive nature, when questionnaires began with the most general questions or when participants were offered an opportunity to opt out of the study.
Context: 
Postal questionnaires are widely used for data collection in epidemiological studies but non-response can reduce effective sample size and can introduce a bias. Finding ways of increasing response rates would improve the quality of health research.
Review CD#: 
CD000008
PEARLS No: 
20
Date: 
May, 2007
Authored by: 
Brian R McAvoy