The Pocket Universal Methods of Design, Revised and Expanded

116	Unobtrusive Measures

Physical evidence, archival records, and nonintrusive observations used for design insight

• This method is used to acquire information without direct participant contact.
• Examples of physical trace erosion measures include wear patterns in floors or grass indicating preferred pedestrian traffic.
• Examples of accretion measures include litter, graffiti, temporary signage, product modifications, or finger-prints to indicate patterns of use.
• Archives are considered unobtrusive measures because they may be accessed without direct contact with participants.
• Observation can be an unobtrusive measure when those being observed do not know it and the researcher has had no input in the situation structure.
• Digital footprints ...