Sizear has worked in various national and international organizations in the research and program sectors. As an anthropologist, he trained in Public Health at the James P. Grant School of Public Health, BRAC University. He has also pursued Urban Development Policy at Erasmus University in the Netherlands. Sizear has authored several publications as a lead and co-author in peer-reviewed, reputed scientific journals. His interest is in the health system and financing, public-private partnership, health-seeking behavior, and human-centric system thinking needed for formulating better health policy to serve people in the complex, growing urban context. He envisions utilizing his expertise to mitigate overwhelming health challenges and bring an evidence-based sustainable solution to create a societal impact.