Principles of survey development for telemedicine applications.

Surveys can be used in the evaluation of telemedicine applications but they must be properly designed, consistent and accurate. The purpose of the survey and the resources available will determine the extent of testing that a survey instrument should undergo prior to its use. The validity of an instrument is the correspondence between what is being measured and what was intended to be measured. The reliability of an instrument describes the 'consistency' or 'repeatability' of the measurements made with it. Survey instruments should be designed and tested following basic principles of survey development. The actual survey administration also requires consideration, for example data collection and processing, as well as the interpretation of the findings. Surveys are of two different types. Either they are self-administered, or they are administered by interview. In the latter case, they may be administered by telephone or in a face-to-face meeting. It is important to design a survey instrument based on a detailed definition of what it intends to measure and to test it before administering it to the larger sample.