Which bias occurs when interviewers influence participants' responses through question wording or presence?

• A. Recall Bias
• B. Information Bias
• C. Selection Bias
• D. Interviewer Bias

Answer: (D)

Interviewer bias happens when the person conducting the interview influences how participants respond, through the way questions are worded, the presence or tone of the interviewer, or nonverbal cues. This creates a systematic error because answers reflect the interviewer's influence rather than the participants’ true experiences or opinions. For example, leading questions or cues can push someone toward a particular response. This is different from recall bias (memory errors by participants), information bias (measurement or data-collection errors), or selection bias (unrepresentative sampling).