The paradata of a survey are data about the process by which the survey data were collected. Paradata are usually "administrative data about the survey."
Example paradata topics about a survey include the times of day interviews were conducted, how long the interviews took, how many times there were contacts with each interviewee or attempts to contact the interviewee, the reluctance of the interviewee, and the mode of communication (such as phone, Web, email, or in person). Thus there are paradata about each observation in the survey. These attributes affect the costs and management of a survey, the findings of a survey, evaluations of interviewers, and inferences one might make about non-respondents.
In principle a survey's metadata includes its paradata.
The term is attributed to Couper (1998).