Which error occurs when the counselor is influenced by extraneous factors during behavioral assessment?

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

Answer: (B)

Observer bias is the tendency for the person doing the observing to let personal expectations, beliefs, or other extraneous factors color how they perceive and rate behavior. In a behavioral assessment, a counselor may have expectations about a client’s progress or be influenced by prior information, and those preconceptions can subtly affect what is noticed, how ambiguous actions are interpreted, and how data are recorded. This creates systematic errors that threaten the accuracy of the assessment. To counteract it, use standardized observation procedures, thorough training, multiple raters, and practices like blind ratings or calibration checks.

The other terms describe different issues: observer drift refers to changes in how criteria are applied over time; observer fatigue is the decline in attention from tiredness; reactivity is when the client changes behavior because they know they’re being observed.