What means interviewer effect?

Interviewer effect refers to the influence that an interviewer may have on respondents during data collection, which can affect the validity and reliability of survey results. This effect can occur through various means, such as the interviewer's tone, body language, or even their demographic characteristics, which may lead respondents to alter their answers based on perceived expectations. Consequently, the interviewer effect can introduce bias, making it important for researchers to minimize its impact during interviews or surveys.