A survey is one of the most popular data collection and research methods across the social sciences and market research. So much so, in fact, that it has become difficult to get people to answer survey questionnaires. Moreover, online surveys have arrived and changed the game a little, making data collection easier and cheaper, but at the same time subject to many biases.

In essence, a survey is a research instrument that usually takes the form of a structured questionnaire. The questionnaire data can be collected through face-to-face or phone interviews or by sending an invitation to answer to the questions by post or via email. In research methodology jargon, survey design is called a cross-sectional study if it is conducted only once, or a longitudinal study if data is collected more than once over time.