Unobtrusive research (or
unobtrusive measures) is a method of data collection used primarily in the
social sciences. The term "unobtrusive measures" was first coined by Webb, Campbell, Schwartz, & Sechrest in a 1966 book titled
Unobtrusive Measures: nonreactive research in the social sciences. The authors described methodologies which do not involve
direct elicitation of data from the research subjects. Unobtrusive measures are contrasted with
interviews and
questionnaires, in that they try to find indirect ways to obtain the necessary data. The unobtrusive approach often seeks unusual data sources, such as garbage,
graffiti and
obituaries, as well as more conventional ones such as published statistics.