Surveys: an introduction.

Surveys are a valuable research tool for studying the knowledge, attitudes, and behavior of a study population. This article explores quantitative analyses of written questionnaires as instruments for survey research. Obtaining accurate and precise information from a survey requires minimizing the possibility of bias from inappropriate sampling or a flawed survey instrument, and this article describes strategies to minimize sampling bias by increasing response rates, comparing responders to nonresponders, and identifying the appropriate sampling population. It is crucial that the survey instrument be valid, meaning that it actually measures what the investigator intends it to measure. In developing a valid survey instrument, it can be useful to adapt survey instruments that were developed by other researchers and to conduct extensive pilot-testing of your survey instrument.