Many researchers planning a quantitative study begin by conducting qualitative interviews to enhance their understanding of the phenomenon under study and to prepare for constructing a questionnaire. The rich insights that in-depth interviews provide into attitudes, values, and behaviors can be invaluable for survey design and measurement decisions. We incorporated a relatively unusual technique, the ethnographic interview, in developing a survey. In this paper, we describe what an ethnographic interview is, compare it to four other kinds of qualitative interviewing styles, and identify specific ways it can contribute to constructing surveys. We illustrate these points with examples from 10 ethnographic interviews that were conducted for a study of social support among inner-city mothers of children who had chronic illnesses.