This paper investigates the impact of interviewer effects on willingness to pay (WTP) estimates. Face-to-face surveys were conducted with two interviewers. Both interviewers used a transcript and conducted the survey at the same location and at same time. We found that responses to the WTP questions differ across eco-labeled products and by interviewer. This interviewer effect is particularly relevant when we analyze the impact on WTP estimates for eco-labeled products grown in countries associated with the origin of one of the interviewers
