Carnegie Mellon University

Stephen Broomell

Stephen Broomell

Assistant Professor, Social and Decision Sciences


I am originally from the greater Cincinnati, Ohio area and grew up in a small town called Madeira.


I attended the Ohio State University and earned a B.S. in Mathematics. I then earned a M.S. in Statistics and a Ph.D. in Quantitative Psychology from the University of Illinois. I was supported by a post-doctoral fellowship through the Intelligence Community, working at the College of Information Sciences and Technology at Penn State University, before joining the faculty of Social and Decision Sciences at Carnegie Mellon University.


My research efforts include the formation and testing of mathematical models to predict human behavior, judgment and decision making, and phenomena related to the understanding of (and integration of) information. My doctoral thesis focused on how decision makers collect and summarize information in the experience based decision making paradigm. Additionally, my previous research produced a model for the factors that influence information overlap in expert opinions, feeding the debate on how many, and which, experts to include in a panel.

I am currently developing a line of research focused on problems of risk communication associated correspondence within the Intelligence Community. The Intelligence Community deals with communication in an extremely uncertain environment. There are many open questions on how to best calibrate confidence and how to ensure that information is treated in the most effective and appropriate way. To address these concerns I have integrated my model of expert opinions with a social network analysis of information flow to examine confidence calibration.

Additionally, I am working on an ongoing collaborative research project studying the perceptions of risk associated with global climate change. Most notably is the analysis of the methods used by the Intergovernmental Panel on Climate Change (IPCC) to communicate uncertainty to the public and to policy makers (Budescu, Broomell, & Por, 2009; Budescu, Por, & Broomell, under review). This work has been cited, and most of our recommendations have been endorsed, by the InterAcademy Council review of the IPCC in August of 2010.


Broomell, S. B., & Budescu, D. V. (2009). Why are experts correlated? Decomposing correlations between judges. Psychometrika, 74 (3), 531-553.

Budescu, D. V., Broomell, S. B., & Por, H. (2009). Improving communication of uncertainty in the reports of the intergovernmental panel on climate change. Psychological Science, 20, 299-308.