Which error results when the observer misses behaviors due to fatigue?

• A. Observer Bias
• B. Observer Fatigue
• C. Observer Drift
• D. Reactivity

Answer: (B)

Fatigue during observation reduces vigilance, making it easy to miss behaviors that are actually occurring. When an observer is tired, attention wanes and quick, brief, or subtle actions can be overlooked, leading to incomplete or biased data. This type of error comes from the observer’s mental or physical state affecting what gets recorded, not from what the participants do or from changes in how criteria are applied over time.

This differs from observer bias, where personal expectations color what is noted; observer drift, where recording criteria slowly shift over time; and reactivity, where participants change their behavior because they know they’re being observed. The described issue centers on the observer’s fatigue as the source of missed observations.