The Extraneous Variable, Instrument Variation

The extraneous variable, instrument variation

A) does not result from variation in administration of the interview.
B) can be acute when there are multiple observers or interviewers.
C) is not attributed to the way with which the interviewer handles the assignment.
D) does not occur if a minor modification is made, such as a slight change in the wording of a specific question so as to make it more understandable without changing its meaning.
E) does not occur with interviews conducted by the same interviewer.