What systematic error is defined as "occurs when criteria by which the rater responds to each item changes?"

A) Observer fatigue
B) Observer bias
C) Observer drift
D) Observer inaccuracy

Observer drift is defined as a systematic error that occurs when the criteria by which the rater responds to each item changes. This can happen due to various reasons such as lack of training or inconsistency in the rater's understanding of the rating scale. Observer fatigue refers to a decrease in the quality of ratings due to the rater being tired or losing focus. Observer bias is a systematic error that occurs due to the rater's personal preferences or prejudices influencing the ratings. Observer inaccuracy refers to random errors that occur due to carelessness or other factors.