Which issue arises when the measurement instrument changes due to prior usage, potentially biasing results?

• A. Instrumentation threat
• B. Maturation
• C. History
• D. Respondent bias

Answer: (A)

When the measurement tool itself changes because of prior use, the data collected at different times aren’t measuring in the same way. This is called instrumentation threat. It biases results because any observed differences between conditions or over time may reflect changes in the instrument or how it’s used (for example, a rater’s scoring criteria drifting, recalibration of a device, or a survey that’s tweaked between assessments) rather than true differences in the phenomenon being studied.

Other threats involve the participants or external factors: maturation is about participants changing over time themselves, history involves external events affecting outcomes, and respondent bias concerns how participants respond rather than how the instrument functions.