Professor Choi's research spans behavioral finance, behavioral economics, household finance, capital markets, health economics, and sociology. His work on default options has led to changes in 401(k) plan design at many U.S. corporations and has influenced pension legislation in the United States and abroad. In other papers, he has investigated topics such as the influence of racial, gender, and religious identity on economic preferences, investor ignorance of mutual fund fees, the effect of deadlines and peer information on savings choices, how retail investor sentiment in China affects stock returns, and the use of subtle planning prompts to increase vaccination rates.

Professor Choi is a recipient of the TIAA-CREF Paul A. Samuelson Award for outstanding scholarly writing on lifelong financial security. He is a member of the FINRA Investor Issues Committee and a TIAA-CREF Institute Fellow.