This paper describes and analyzes the successful collaboration between the Philadelphia Affordable Housing Coalition and the Cartographic Modeling Laboratory at the University of Pennsylvania. This collaboration resulted in a research study that helped the Coalition secure an additional $10 million for affordable housing in Philadelphia. The perspectives of the activist and researcher on the collaboration are presented in their own voices and they describe their expectations, efforts to build relationships, define roles, and deal with different work styles and culture. Recommendations for building effective research partnerships are also provided.