92 Unobtrusive Measures
Unobtrusive methods are used to acquire information without direct contact with participants, through nonreactive physical traces, archives, and observations.
Unobtrusive and trace measures were proposed in the late 1960s in response to the inherent bias evident in self-report and direct-contact methods such as surveys and interviews.1 The method uses physical evidence from events that have already occurred, archival records, and nonintrusive observations. The measures are designed to be flexible and creative, promoting the use of unusual data sources. They should be critically triangulated with other methods, ...