Demographics gather data from the respondent, such as age, gender, education, income, social class, job title, purchasing behaviour and so on. It is used to segment respondents and pre-target them. The demographics part of a questionnaire gathers data used in analsing results obtained from different sub-groups of the respondents. The final aspect of the demographics section depends on the nature and objectives of the project.
Also see: Questionnaire, Self completion questionnaire