Questionnaire designing and validation

Measurement is an essential activity of medical science. In order to acquire data about people, objects, and events proper data collection tools need to be designed which can measurethings of scientific interest. Questionnaire is one of the most important techniques to collect data. It is a common experience that many studies focus on similar objective and theme but have entirely different questionnaires. It is extremely important for a researcher to know the importance of a proper questionnaire and whether it measures what it is intended to measure. Composing of a questionnaire is always much more complex than expected and great attention is required to its flow, format and length. Making an individual question is a tedious task and validating this questionnaire is another challenge which at times is over looked. Consideration should be given accordingly on whether the questionnaire will measure quantitative or qualitative data, and what would be its mode of administration. The aim of this paper is to give a basic introduction and broad overview to the readers on questionnaires for epidemiological studies.