Stanley has particular expertise in the design, conduct, management and analysis of clinical, behavioural, and health systems interventions that have a population health impact, with an extensive background assessing the intervention effectiveness on sexual and reproductive health among vulnerable groups, including sex workers, men who have sex with men, pregnant women and children. He has led more than 25 research studies as Principal Investigator and over 20 as co-investigator, including pragmatic trials, (cluster) randomised controlled trials, quasi-experimental studies, cohort studies, diagnostic performance studies, qualitative inquiries, and numerous implementation science and capacity building projects. Since 2019, Stanley has made the work around the impacts of climate change on sexual reproductive health a priority, and has been particularly assessing the health effects and community perceptions of extreme heat on maternal and child heath in Africa.

Stanley has supervised more than 15 PhD candidates to completion as Primary Supervisor. The majority of these students came from low- and middle-income countries including Kenya, Mozambique, Myanmar, China, Vietnam and India. As the foundation Chair of the Department of Population Health at the Aga Khan University, he developed the curriculum for a two-year full-time Masters in Population Health Science, and contributed to the Master of Medicine training on research methods and dissertation supervision.