To understand how community leadership can be incorporated in health research, this chapter tracks the first stages of a population size estimate in six Eastern Caribbean countries, with a focus on one of the countries, Grenada. Grenada is a small island state and an upper-middle-income country. While external aid previously funded much of the region’s HIV response, global health agencies are transitioning out to prioritize reaching the “end of AIDS” in high-prevalence, lower-income countries. However, criminalization and discrimination contribute to lack of resources for key populations in middle-income countries. In Grenada, abrupt US aid withdrawal left community groups dormant, without funding or staffing. In past studies, after the data was extracted, local groups saw no results of the research. A regional civil society group, Caribbean Vulnerable Communities (CVC), will lead this new population size estimation study. An ethnographic study of the CVC study highlights the challenges with finding and counting hidden key populations. CVC must restart old networks and rebuild trust. The activists negotiate for power and control of the data, using their arduous research to position revived community groups at the center of national HIV responses; hoping that the research will produce “something more than just data”.