This paper is the first in MDRC's series on research methodology to examine the use of ethnographic interviews, focus groups, and other intensive qualitative methods in social policy research. Based on interviews with senior staff at MDRC and using four major MDRC projects as case studies, it highlights the unique contributions that qualitative methods can make to efforts to understand the effects of social programs and discusses the challenges of integrating qualitative research into the design, analysis, and presentation of social policy evaluations. Itself an example of illuminating qualitative research, this review of MDRC's experiences culminates in specific guidelines for getting the most out of qualitative methods.