Tom Stewart, August 2009
Thomas R. Stewart, Research Professor Emeritus, Center for Policy Research and Department of Pubic Administration and Policy, Rockefeller College of Public Affairs and Policy
Milne 300, 135 Western Avenue
University at Albany
State University of New York
Albany, NY 12222

Research and teaching interests

I am interested in analyzing expert or professional judgment under conditions of complexity and uncertainty. Why are some judges more accurate than others? How can judgments be improved? I use Brunswik's lens model framework and the lens model equation to analyze various components of expert skill. I am particularly interested in practical applications of judgment and decision research to public policy issues and to improving professional judgment. Recently, I have been studying how people learn decision thresholds when they do not get complete feedback.

For more information, see the Center for Policy Research and the home page for my course "Seminar on Judgment and Decision making Behavior."

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Recent papers and publications

Doherty, Michael E., Stewart Thomas R., and Holzworth, R. James (2021), "Noise" and Social Judgment Theory: A Commentary on Kahneman, Sibony and Sunstein. Brunswik Society Newsletter, 36, 56-66. Full text pdf

Holzworth, R. J., Stewart, T. R., and Mumpower, J. L. (2018) Detection and Selection Decisions with Conditional Feedback: Interaction of Task Uncertainty and Base Rate. Journal of Behavioral Decision Making, doi: 10.1002/bdm.2062. Online Abstract

Stewart, T. R., Mumpower, J. L., & Holzworth, R. J. (2012). Learning to make selection and detection decisions: The roles of base rate and feedback. Journal of Behavioral Decision Making, 25(5), 522-533. Online Abstract

Weaver, E. A., & Stewart, T. R. (2012). Dimensions of judgment: Factor analysis of individual differences. Journal of Behavioral Decision Making (Special issue on individual differences), 25, 402-413. Online Abstract

Ghaffarzadegan, N., & Stewart, T. R. (2011). An Extension to the constructivist coding hypothesis as a learning model for selective feedback when the base rate is high. Journal of Experimental Psychology: Learning, Memory, and Cognition, 37(4), 1044-1047.

Stewart, T. R. (2009). The lens model. In M. Kattan (Ed.), Encyclopedia of Medical Decision Making. Thousand Oaks, CA: Sage Publications, Inc.

Stewart, T. R. (2009). Social judgment theory. In M. Kattan (Ed.), Encyclopedia of Medical Decision Making. Thousand Oaks, CA: Sage Publications, Inc.

Martinez-Moyano, I. J., Rich, E., Conrad, S., Andersen, D. F., & Stewart, T. R. (2008). A Behavioral Theory of Insider-Threat Risks: A System Dynamics Approach. ACM Transactions on Modeling and Computer Simulation, 18(2), Article 7.

Horrey, W. J., Wickens, C. D., Strauss, R., Kirlik, A., Stewart, T.R. (2006). Supporting situation assessment through attention guidance and diagnostic aiding: The benefits and costs of display enhancement on judgment skill. In Kirlik, A. (Ed.) Adaptive Perspectives on Human-Technology Interaction: Methods and Models for Cognitive Engineering and Human-Computer Interaction. New York: Oxford University Press.

Stewart, T.R. and Mumpower, J. L. (2004). Detection and selection decisions in the practice of screening mammography. Journal of Policy Analysis and Management, 23(4), 908-920.

Stewart, T. R., Pielke, R. Jr., Nath, R. (2004). Understanding user decision making and value of improved precipitation forecasts: Lessons from a case study. Bulletin of the American Meteorological Society, 85(2), 223-235.

Sorum, P. C., Stewart, T., Mullet, E., González-Vallejo, C., Shim, J., Chasseigne, G., Muñoz Sastre, M. T., and Grenier, B. (2002). Does choosing a treatment depend on making a diagnosis? U.S. and French physicians' decision making about acute otitis media. Medical Decision Making, 22(5), 394-402.

Mumpower, J. L., Nath, R., and Stewart, T. R. (2002) Affirmative action, duality of error, and the consequences of mispredicting the academic performance of African-American college applicants. Journal of Policy Analysis and Management, 21(1), 63-77.

Sorum, P. C., Shim, J., Chasseigne, G., Mullet, E., Muñoz Sastre, M. T., Stewart, T., González-Vallejo, C. (2002). Do Parents and Physicians Differ in Making Decisions About Acute Otitis Media? The Journal of Family Practice, 51, 51-57. (

Hammond, K. R. and Stewart, T. R. (Eds.) (2001). The Essential Brunswik: Beginnings, Explications, Applications. New York: Oxford University Press. (Table of Contents)

Stewart, T. R. (2001). Improving reliability of judgmental forecasts. In J. S. Armstrong (Ed.), Principles of Forecasting: A Handbook for Researchers and Practitioners . Norwell, MA: Kluwer Academic Publishers.

Stewart, T. R. (2000).  Uncertainty, judgment, and error in prediction.  In Sarewitz, D., Pielke, R. Jr., and Byerly, R. Jr. (Eds.), Prediction:  Decision Making and the Future of Nature.  Washington D. C.: Island Press.

Stewart, T. R. (2000). Modernization: The Challenge Continues (Guest editorial). Weatherzine, Number 20, February;

Stewart, T. R. (1999). Commentary on "The Delphi technique as a forecasting tool: Issues and analysis" by Rowe and Wright. Journal of Forecasting, 15, 380-381.

Way, B. B., Allen, M. H., Mumpower, J. L., Stewart, T. R., & Banks, S. M. (1998). Interrater agreement among psychiatrist in psychiatric emergency assessments. American Journal of Psychiatry, 155(10), 1423-8.

González-Vallejo, C., Sorum, P.C., Stewart, T.R., Chessare, J.B., Mumpower, J. (1998).  A study of physicians’ diagnostic judgments and treatment decisions for acute otitis media in children.  Medical Decision Making, 18, 149-162.

Chasseigne, G., Mullet, E., & Stewart, T. R. (1997). Aging and multiple cue probability learning:  The case of inverse relationships. Acta Psychologica, 97, 235-252.

Stewart, T. R., Roebber, P. J. and Bosart, L. F. (1997). The importance of the task in analyzing expert judgment.  Organizational Behavior and Human Decision Processes, 69, 205-219.

Stewart, T.R. (1997).  Forecast value:  Descriptive decision studies.  In Katz, R.W.  and Murphy, A.H. (Eds.), Economic value of weather and climate forecasts. New York:  Cambridge University Press.

Mumpower, J. L. and Stewart, T. R. (1996).  Expert judgement and expert disagreement.  Thinking and Reasoning, 2, 191-211.

Stewart, T. R. (1995). On statistical terminology. Teaching Statistics, 17, 103.

Joyce, C. R. B. and Stewart, T. R. (1994). Applied research on judgment: What should happen, Acta Psychologca, 87, 217-227.

Stewart, T. R. and Lusk, C. M. (1994). Seven components of judgmental forecasting skill: Implications for research and the improvement of forecasts. Journal of Forecasting, 13, 575-599. (Reprinted in Connolly, T., Arkes, H. R., and Hammond K. R., Eds., (2000) Judgment and Decision Making: An Interdisciplinary Reader, Second Edition. New York: Cambridge University Press.)

Heideman, K.F., Stewart, T.R., Moninger, W.R. and Reagan-Cirincione, P. (1993). The weather information and skill experiment (WISE): The effect of varying levels of information on forecast skill. Weather and Forecasting, 8, 25-36.

Stewart, T.R., Moninger, W.R., Heideman, K.F., and Reagan-Cirincione, P. (1992). Effects of improved information on the components of skill in weather forecasting. Organizational Behavior and Human Decision Processes, 53, 107-134.

Shanteau, J. and Stewart, T.R. (1992). Why study expert decision making? Some historical perspectives and comments. Organizational Behavior and Human Decision Processes, 53, 95-106.

Stewart, T.R., Reagan-Cirincione, P., and Moninger, W.R. (1992). Coping with the meteorological data explosion through simulated group forecasting. Preprint volume, Fourth AES/CMOS Workshop on Operational Meteorology, Whistler, B.C., September, 15-18, 39-48.

Stewart, T.R., Mumpower, J.L., and Reagan-Cirincione, P. (1992). Scientists' opinions about global climate change: Summary of the results of a survey. NAEP (National Association of Environmental Professionals) Newsletter, 17(2), 6-7.

Stewart, T.R. (1991). Scientists' uncertainty and disagreement about global climate change: A psychological perspective, International Journal of Psychology, 26, 565-573.

Stewart, T.R. and Reagan-Cirincione, P. (1991). Coefficients for debiasing forecasts, Monthly Weather Review, 119, 2047-2051.

Ely, D. Leary, J.T., Stewart, T.R., and Ross, D.M (1991). The establishment of the Denver Visibility Standard. Proceedings of the Air and Waste Management Association, 84th Annual Meeting, Vancouver, B.C., June 16-21, 1991.

Stewart, T.R. (1990). A Decomposition of the correlation coefficient and its use in analyzing forecasting skill, Weather and Forecasting, 5, 661-666.

Lusk, C.M., Stewart, T.R., Hammond, K.R. and Potts, R.J. (1990). Judgment and decision making in dynamic tasks: The case of forecasting the microburst, Weather and Forecasting, 5, 627-639.

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 Education and experience

Ph.D. in Measurement and Differential Psychology, University of Illinois 
Bachelor of Arts in Psychology, College of Wooster 
Current Position
Research Professor Emeritus, Center for Policy Research and Department of Public Administration and Policy,
Rockefeller College of Public Affairs and Policy
University at Albany
Previous Positions
Director, Center for Policy Research, Rockefeller College of Public Affairs and Policy, University at Albany (1997-2001, 2007-2010)

Scientist III, Environmental and Societal Impacts Group, National Center for Atmospheric Research, Boulder, Colorado (1980-1986) 

Associate Professor (tenured), Graduate School of Public Affairs, University of Colorado at Denver (1974-1981) 

Faculty Fellow, National Association of Schools of Public Affairs and Administration, serving in the Office of Coastal Zone Management, National Oceanic and Atmospheric Administration, Washington, D.C. (1978-1979) 

Research Associate, Center for Research on Judgment and Policy, Institute of Cognitive Science, University of Colorado (1970-1988) 

Assistant Professor, Division of Management Science, Graduate School of Business Administration, University of Colorado (1972-1974) 

Professional Affiliations
The Brunswik Society 
Judgment and Decision Making Society 
European Association for Decision Making 
Society for Medical Decision Making 
American Psychological Society 
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Married since 1968 to Jeanette Scotland. Two children: Tim Scotland-Stewart graduated from SUNY, Albany and is living in Denver with our two grandchildren. He completed his Masters degree in the Building Systems Program in the Department of Civil, Environmental, and Architectural Engineering of the College of Engineering and Applied Science at the University of Colorado at Boulder and is now Director of Product Management at Edo. Laurel Scotland-Stewart earned her Ph.D. in Philosophy from Stanford University and has taught at Stanford and Reed College. She is currently teaching at the University of San Francisco, writing, and acting

Spare time activities include photography, digital imaging, pickleball, and hiking.

My mother, Emily Trent Stewart, died in 1989. My father, Ray Stewart died in 2003. He wrote several novels, and some are available on Kindle. See his Amazon Author page.

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