Which type of error occurs when assessor expectations influence results?

• A. Observer bias error
• B. Instrumentation error
• C. Measurement error
• D. Random error

Answer: (A)

The type of error that occurs when assessor expectations influence results is known as observer bias error. This bias arises when the beliefs, expectations, or preconceptions of the assessor inadvertently affect their judgments or evaluations during the assessment process. For example, if an assessor expects a certain outcome based on prior knowledge or experiences, they may unconsciously interpret the data or results in a way that confirms their expectations, leading to skewed results.

Observer bias can significantly affect the validity of a study, as it can create inconsistencies in how data is collected or analyzed. It is crucial to minimize this type of bias by employing blinding techniques, ensuring that assessors are unaware of the conditions or group assignments of participants.

In contrast, instrumentation error refers to inaccuracies caused by the equipment or tools used for measurement rather than human influence. Measurement error encompasses all inaccuracies in the data collection process, which may stem from various factors, including human error or flaws in the measurement process, while random error is the inherent variability in data that occurs due to chance. Recognizing observer bias error is essential in maintaining the integrity and reliability of research findings.