Colleen Hanrahan in an Assistant Scientist the Epidemiology Department at the Johns Hopkins Bloomberg School of Public Health in Baltimore, MD, USA. Her research is focused on identifying better ways to find cases of tuberculosis, especially within the context of the HIV pandemic. In particular, she is interested in using operational research to examine the impact and appropriate implementation of both new and existing diagnostic tests as well as active or intensified case finding strategies. She is also interested in the impact of local, national and international TB control policies on TB epidemiology. She employs a mix of standard epidemiologic methods as well as economic evaluation in her work.