The Economics Department at Princeton is excited to announce that Professors Mira Frick and Ryota Iijima will join the department this fall from Yale University.

Frick and Iijima are microeconomic theorists and frequent research collaborators. In their research, Frick, Iijima, and their coauthors work on theoretical models of how individuals acquire and process information and make decisions, in particular in complex environments. 

“A traditional modeling approach in economics is that people correctly understand their environment and the uncertainty they face and are able to make optimal decisions based on this,” said Frick. “Departing from this approach, several of our papers provide tools to analyze people’s learning and decisions when they misperceive some aspects of their environment or have ambiguous beliefs.”

For example, in past work with their coauthor Yuhta Ishii (Pennsylvania State University), they show that even slight misperceptions of other people’s characteristics, such as their tastes or risk attitudes, can lead to dramatic failures of learning about economic fundamentals. They also study how misperceiving one’s peers to be more representative of the broader population than they actually are can polarize behavior in society (for example, exacerbating socioeconomic disparities in education investment).

“Some of our more recent work explores a different direction,” said Iijima. “In settings where exactly optimal contracts or mechanisms are complicated to determine, are there simple policies that are approximately optimal?” 

For example, in “Monitoring with Rich Data,” they study an employer who designs a wage contract to incentivize her employees to exert effort. Optimal contracts can look complicated and unrealistic. However, they show that when the employer has access to rich monitoring data about workers’ effort, a simple and frequently used class of contracts—single-bonus schemes—is approximately optimal, whereas other common contracts (e.g., linear contracts) can be highly suboptimal.

In Spring 2025, Frick and Iijima look forward to co-teaching a graduate-level class on these and related topics.

Frick currently serves as an associate editor at the American Economic Review: Insights, the Journal of Political Economy, and Theoretical Economics. She received an Alfred P. Sloan Research Fellowship in 2022. Iijima is a 2024 Sloan Research Fellow and serves as an associate editor at the Japanese Economic Review and the Journal of Economic Theory.

Frick is originally from Germany. She received a Ph.D. in Business Economics from Harvard University, following undergraduate and graduate-level studies in Mathematics and Philosophy at Oxford University, Ecole Normale Supérieure (Paris), and UC Berkeley. Iijima hails from Japan. He holds B.A. and M.A. degrees in Economics from the University of Tokyo and a Ph.D. in Economics from Harvard University.

Frick and Iijima previously spent a sabbatical at Princeton in 2018-2019. 

“I learned a tremendous amount that year from interacting with the outstanding colleagues and Ph.D. students in the micro theory and behavioral and experimental groups,” said Frick. “I am really excited to continue learning from them.”

Iijima found the environment at Princeton “very conducive to research productivity.”

“I hope the years to come will be just as stimulating and productive,” he said.