Unobtrusive measures in behavioral assessment.
Obtrusive observation can distort data—use unobtrusive sources like archival records or physical traces when possible.
01Research in Context
What this study did
McMillan (1979) wrote a think-piece. He asked: what if the way we watch behavior changes it?
He listed quiet ways to measure without people noticing. Think old attendance logs, worn spots on the carpet, or security video.
What they found
The paper says obvious watching can make clients act different. When they know you are scoring, they may try harder or freeze up.
Unobtrusive sources give cleaner data. They also protect dignity—no one feels like a lab rat.
How this fits with other research
van Timmeren et al. (2016) built a pick-list for choosing measures. Their model tells you when to pick low-reactive tools—just what McMillan (1979) wanted.
Granieri et al. (2020) showed the same idea in sensory work. Questionnaires (reactive) and quiet behavioral tests (unobtrusive) gave different answers.
Pitchford et al. (2019) updated the call. They ask for finer grain today, but still warn: if your measure changes the behavior, the data lie.
Why it matters
Next time you take baseline, look for a silent source first. Count milk-carton sales to track cafeteria use, or scan the swipe-card log for arrival time. If you must observe live, stand behind a one-way mirror or use a hidden camera. Your data will look more like real life—and your treatment decisions will hit the mark.
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02At a glance
03Original abstract
A major distinguishing characteristic of behavioral assessment is the direct assessment of overt behavior. Direct assessment is assumed to provide a sample of behavior that reflects client performance in the situation in which behavior is assessed, even if the assessment procedures were not implemented. Yet, in the majority of investigations, behavioral assessment procedures are obtrusive, i.e., subjects are aware that their behavior is being assessed. The potential problem with obtrusive assessment is that it may be reactive, i.e., affect how subjects perform. Recent research has demonstrated that obtrusive observations often are reactive and that behaviors assessed under obtrusive and unobtrusive conditions bear little relation. From methodological and applied perspectives, additional attention needs to be given to unobtrusive measures of behavior change. The present paper illustrates unobtrusive measures in behavior modification including direct observations, archival records, and physical traces of performance. In addition, validation and assessment problems, questions about the obtrusiveness of the measures, and ethical issues are discussed.
Journal of applied behavior analysis, 1979 · doi:10.1901/jaba.1979.12-713