Sanjay Kumar is a Professor at the Centre for the Study of Developing Societies (CSDS), Delhi, and Codirector, Lokniti, a research program of the CSDS. Trained in survey research at the Summer School in the University of Michigan, he has directed various national and state-level surveys conducted by the CSDS,including the series of National Election Studies (NES) conducted during the Lok Sabha elections of 1996, 1998, 1999, 2004, and 2009. Besides the NES, he has also directed various state-level studies. His research draws heavily from empirical studies. He is also interested in mapping the changing patterns of democracy. He has been the country coordinator (India) for the State of Democracy in South Asia study conducted by the CSDS and a core team member of the Asian Barometer Study conducted in different countries. He has also been a member of the team of international observers for observing elections in various countries. He is also a member of the drafting committee for the charter on Free and Fair elections in Asia.

His most recent book is Changing Electoral Politics in Delhi: From Caste to Class (SAGE Publications 2013). His other books are Measuring Voting Behaviour in India (with Praveen Rai; SAGE Publications 2013), Rise of the Plebeians? The Changing Face of Indian Legislative Assemblies (coedited with Christophe Jaffrelot 2009), and Indian Youth in a Transforming World: Attitudes and Perceptions (with Peter Ronald DeSouza and Sandeep Shastri; SAGE Publications 2009). He also writes regularly for national and regional newspapers, and is a recognized face on electronic media as an election expert.