Larry V. Hedges

Board of Trustees Professor of Statistics and Social Policy,
Faculty Fellow, Institute for Policy Research, Northwestern University
PhD, Mathematical Methods in Educational Research, Stanford University, 1980
l-hedges@northwestern.edu
Curriculum Vitae

A national leader in the fields of educational statistics and evaluation, Larry V. Hedges joined the Northwestern faculty in 2005. He is one of eight Board of Trustees Professors at Northwestern, the university’s most distinguished academic position. He holds appointments in statistics, psychology, and education and social policy. Previously, he was the Stella M. Rowley Distinguished Service Professor at the University of Chicago.

Hedges’ research straddles many fields—in particular those of sociology, psychology, and educational policy. He is best known for his work to develop statistical methods for meta-analysis (a statistical analysis of the results of multiple studies that combines their findings) in the social, medical, and biological sciences. It is a key component of evidence-based social research. Examples of some his recent studies include: understanding the costs of generating systematic reviews, differences between boys and girls in mental test scores, the black-white gap in achievement test scores, and frameworks for international comparative studies on education.

Widely published, he has authored or co-authored numerous journal articles and five books, including the seminal Statistical Methods for Meta-Analysis: A Practical Guide to Modern Methods of Meta-Analysis (with I. Olkin) and The Handbook of Research Synthesis (with H. Cooper and J. Valentine).

He is an elected member of the National Academy of Education and is a fellow of the American Academy of Arts and Sciences, the American Statistical Association, the American Psychological Association, and the American Educational Research Association. He is vice chair of the board of trustees of the Russell Sage Foundation, co-chair pro temp of the board of the Society for Research on Educational Effectiveness, and president of the Society for Research Synthesis Methods.

Current Projects

A Training Institute on Randomized Controlled Trials in Educational Research, funded by the U.S. Institute of Education Sciences. This project provides a series of intensive two-week summer institutes for research professionals who desire advanced training in the design, conduct, and analysis of large scale randomized experiments in education.

The Social Distribution of Academic Achievement in America, funded by the Spencer Foundation. In this project, Hedges and his colleagues seek to document the social distribution of academic achievement in the U.S. By examining various achievement gaps (by gender, race, ethnicity, social class, etc.) in different ways, they come to understand how the social distribution of achievement has changed over the last few decades. A major part of this study evaluates patterns of between- and within-school variability of student achievement. They also examine whether different sources of evidence lead to the same conclusions, that is, they seek to triangulate whenever possible. Finally, the researchers study the—somewhat limited—longitudinal evidence, attempting to coordinate it with repeated cross-sectional evidence. They expect that combining such data may help us understand the emergence of differences in patterns of academic achievement between important population sub-groups. How large, for example, are achievement gaps when students enter school? How do these gaps grow over time? How does social context and school context affect the initial gaps and their growth over time? Do between-school differences grow over time and what is associated with this growth?

The Center for Advancing Research and Communication in Science, Technology, Engineering, and Mathematics (ARC), funded by the National Science Foundation conducts research to understand the factors that are essential for scaling-up promising educational models, programs, and strategies, and develop methodological tools and research designs for scale-up. ARC also supports investigators conducting NSF supported research and works with these projects to build capacity by strengthening the community of scholars working to understand the factors that impede and enhance scale-up and building capacity to share this knowledge with practitioners, policymakers, and other educational researchers.

Presentation and Combination of the Results of Multi-site Randomized Experiments in Education, funded by the Institute of Education Sciences (IES). Much of the work on representing the results of experiments via measures of effect size and the combination of these effect sizes across studies has focused on simple, single-site experiments. The recent interest in larger multi-site and group randomized experiments in education requires new methods. This project involves basic research on how to represent the results of multi-site randomized experiments, and how to combine evidence from studies of this type with those from other multi-site randomized trials and from smaller studies.

Selected Publications

Books and Monographs

Cooper, H. M., L. V. Hedges, and J. Valentine, eds. 2009. The Handbook of Research Synthesis and Meta-Analysis, 2nd Edition. New York: The Russell Sage Foundation.

Borenstein, M., L. V. Hedges, J. P. T. Higgins, and H. R. Rothstein. 2009. Introduction to Meta-Analysis. London: Wiley.

Hedges, L. V., and B. Schneider, eds. 2005. The Social Organization of Schooling. New York: The Russell Sage Foundation.

Cooper, H. M. and L. V. Hedges, eds. 1994. The Handbook of Research Synthesis. New York: The Russell Sage Foundation.

Draper, D., D. P. Gaver, P. K. Goel, J. B. Greenhouse, L. V. Hedges, C. N. Morris, J. R. Tucker, and C. Waternaux. 1993. Combining Information: Statistical Issues and Opportunities for Research. Washington, D.C.: American Statistical Association.

Cook, T., H. M. Cooper, D. Cordray, L. V. Hedges, R. J. Light, T. Louis, and F. Mosteller. 1991. Meta-Analysis for Explanation. New York: The Russell Sage Foundation.

Hedges, L. V., J. A. Shymansky, and G. Woodworth. 1989. A Practical Guide to Modern Methods of Meta-Analysis. Washington, D.C.: National Science Teachers Association.

Hedges, L. V., and I. Olkin. 1985. Statistical Methods for Meta-Analysis. New York: Academic Press.


Scholarly Articles (selected)

Statistics

Shadish, W. R., D. M. Rindskopf, and L. V. Hedges. 2008. The state of the science in the meta-analysis of single-case experimental designs. Evidence-Based Communication Assessment and Intervention 2(3): 188–96.

Hedges, L. V., and E. Hedberg. 2007. Interclass correlation values for planning group-randomized trials in education. Educational Evaluation and Policy Analysis 29(1): 60–87.

Hedges, L. V. 2007. Correcting a significance test for clustering. Journal of Educational and Behavioral Statistics 32(2): 151–79.

Hedges, L. V. 2007. Effect sizes in cluster-randomized designs. Journal of Educational and Behavioral Statistics. 32(4): 341–70.

Hedges, L. V. 2007. Meta-analysis. In The Handbook of Statistics, ed. C. R. Rao, p. 919-53. Amsterdam: Elsevier.

Hedges, L. V., and J. Vevea. 2005. Selection model approaches to publication bias. Pages 145-174 in Publication Bias in Meta-Analysis, ed. H. Rothstein, A. Sutton, and M. Borenstein. New York: Wiley.

Hedges, L. V., and T. D. Pigott. 2004. The power of statistical tests for moderators in meta-analysis. Psychological Methods 9:426–45.

Hedges, L. V., and T. D. Pigott. 2001. The power of statistical tests in meta-analysis. Psychological Methods 6:203–17.

Educational Policy

Hedges, L. V., and J. Hanis. 2009. Can non-randomized studies provide evidence of causal effects? A case study using the regression discontinuity design. In Education Research On Trial, ed. P. B. Walters, A. Lareau, and S. H. Ranis. New York: Routledge.

Konstantopoulos, S., and L. V. Hedges. 2008. How large an effect can we expect from school reforms? Teachers College Record 110(8): 1611–38.

Hedges, L. V., and E. Hedberg. 2007. Interclass correlation values for planning group-randomized trials in education. Educational Evaluation and Policy Analysis 29(1): 60–87.

Nye, B., L. V. Hedges, and S. Konstantopoulos. 2004. How large are teacher effects? Educational Evaluation and Policy Analysis 26:237–57.

Nye, B., L. V. Hedges, and S. Konstantopoulos. 2004. Do minorities experience greater lasting benefits from small classes?: Evidence from a five year follow-up of the Tennessee class size experiment. Journal of Educational Research 97:94-100.

Hedges, L. V., S. Konstantopoulos, and A. Thoreson. 2003. Studies of technology implementation and effects. In Evaluating educational technology: Effective research designs for improving learning, ed. G. D. Haertel and B. Means, 187–204. New York: Teachers College Press.

Nye, B., L. V. Hedges, and S. Konstantopoulos. 2002. Do low achieving students benefit more from small classes?: Evidence from the Tennessee class size experiment. Educational Evaluation and Policy Analysis 24:201-17.

Nye, B., L. V. Hedges, and S. Konstantopoulos. 2000. The effects of small classes on achievement: The results of the Tennessee class-size experiment. American Educational Research Journal 37:123–51.

Nye, B., L. V. Hedges, and S. Konstantopoulos. 2000. Do minorities and the disadvantaged benefit more from small classes?: Evidence from the Tennessee class-size experiment. American Journal of Education 109:1–26.

Nye, B., L. V. Hedges, and S. Konstantopoulos. 1999. The long-term effects of small classes: A five-year follow-up of the Tennessee class-size experiment. Educational Evaluation and Policy Analysis 21:127–42.

Psychology

Huttenlocher, J., L. V. Hedges, E. Crawford, and B. Corrigan. 2007. Estimating stimuli in contrasting categories: Truncations due to boundaries. Journal of Experimental Psychology 136(3): 502–19.

Huttenlocher, J., M. Vasilyeva, J. Vevea, and L. V. Hedges. 2007. Varieties of speech in young children. Developmental Psychology 43(5): 1062–83.

Crawford, E., J. Huttenlocher, and L. V. Hedges. 2006. Within-category feature correlations and Bayesian adjustment strategies. Psychonomic Bulletin and Review, 13:245-50.

Klibanoff, R., S. C. Levine, J. Huttenlocher, M. Vasilyeva, and L. V. Hedges. 2006. Preschool children’s mathematical knowledge: The effect of teacher input. Developmental Psychology, 42:59-69.

Huttenlocher, J., L. V. Hedges, B. Corrigan, and E. Crawford. 2004. Spatial categories and the estimation of location. Cognition 93:75-97.

Huttenlocher, J., L. V. Hedges, and J. L. Vevea. 2000. Why do categories affect stimulus judgment? Journal of Experimental Psychology 129:1-22.

Sociology

Konstantopoulos, S., M. Modi, and L. V. Hedges. 2001. Who are America’s gifted? American Journal of Education 109:344–82.

Hedges, L. V., and A. Nowell. 1999. Changes in the black-white gap in achievement test scores: The evidence from nationally representative samples. Sociology of Education 72:111–35.

Nowell, A., and L. V. Hedges. 1998. Trends in gender differences in academic achievement from 1960 to 1994: An analysis of differences in mean, variance and extreme scores. Sex Roles 39:21–43.

Hedges, L. V., and A. Nowell, A. 1998. Are black-white differences in test scores narrowing? in The Black White Test Score Gap, ed. C. Jencks and M. Phillips, 254-81. Washington, DC: The Brookings Institution.

Research in Biology, Medicine or Public Health Publications

Mullen, P. D., G. Ramírez, D. Strouse, L. V. Hedges, and E. Sogolow. 2002. Meta-analysis of the effects of behavioral HIV prevention interventions on the sexual risk behavior of sexually experienced adolescents in U.S.-controlled studies. Journal of Acquired Immune Deficiency Syndromes 30:S94–105.

Hedges, L. V., W. Johnson, S. Semaan, and E. Sogolow. 2002. Theoretical issues in the synthesis of HIV prevention research. Journal of Acquired Immune Deficiency Syndromes 30:S8–14.

Neuman, M. S., W. D. Johnson, S. Semaan, S. A. Flores, G. Peersman, L. V. Hedges, and E. D. Sogolow. 2002. Review and meta-analysis of HIV prevention intervention research for heterosexual adult population in the United States. Journal of Acquired Immune Deficiency Syndromes 30:S106-117.

Semaan, S., D. DesJarlais, E. Sogolow, W. Johnson, L. V. Hedges, G. Ramírez, S. Flores, L. V. Norman, M. Sweat, and R. Needle. 2002. A meta-analysis of the effect of HIV prevention programs on the sex behaviors of drug users in the United States. Journal of Acquired Immune Deficiency Syndromes 30:S73-93.

Johnson, W., L. V. Hedges, G. Ramírez, S. Seeman, L. Norman, E. Sogolow, M. Sweat, and M. Diaz, 2002. HIV prevention research for men who have sex with men: A systematic review and meta-analysis. Journal of Acquired Immune Deficiency Syndromes 30:S118–130.

Hedges, L. V., J. Gurevitch, and P. Curtis. 1999. The meta-analysis of response ratios in experimental ecology. Ecology 80:1150–56.