Associate Professor of Statistics
Ph.D., Harvard University, 1991

Summary of research interests

Dr. Schafer has developed techniques for analyzing incomplete data and incorporating missing-data uncertainty into statistical inference. These techniques include both asymptotic approximations and simulation via multiple imputation, in which missing data are replaced by multiple simulated values. He has worked to develop general-purpose algorithms and software for the analysis of incomplete multivariate data.

He has also been extensively involved with several projects undertaken by the Bureau of the Census, including the Post-Enumeration Survey to measure the undercount in the 1990 census.

His research interests currently include the formal assessment of uncertainty due to missing data and other sources of nonsampling error in sample surveys, techniques for computation and stimulation of Bayesian posterior distributions, and parametric inference in sample surveys.

Representative publications

J. L. Schafer. 2001. Multiple imputation with PAN. New Methods for the Analysis of Change, A. G. Sayer and L. M. Collins (eds.). Washington, D. C.: American Psychological Association, pp. 355-377.

J. L. Schafer and N. Schenker. 2000. Inference with imputed conditional means. Journal of the American Statistical Association 95: 144-154.

J. W. Graham and J. L. Schafer, J. L. 1999. On the performance of multiple imputation for multivariate data with small sample size. Statistical Strategies for Small Sample Research, R. Hoyle (ed.). Thousand Oaks, Calif.: Sage Publications Ltd., pp. 1-29.

J. L. Schafer. 1999. Multiple imputation: a primer. Statistical Methods in Medical Research 8: 3-15.

J. W. Graham, S. M. Hofer, S. I. Donaldson , D. P. MacKinnon, and J. L. Schafer. 1997. Analysis with missing data in prevention research. The Science of Prevention: Methodological Advances from Alcohol and Substance Abuse Research, K. Bryant, M. Windle, and S. West (eds.). Washington, D.C.:American Psychological Association, pp. 325-366.

J. L. Schafer. 1996. Comment on “Statistical inference and Monte Carlo algorithms,” by G. Casella, Test 5: 320-321

J. L. Schafer. 1993. Comment on “Assessing between-block heterogeneity within the post-strata of the 1990 Post-Enumeration Survey” by N. Hengartner and T. P. Speed. Journal of the American Statistical Association 88: 1125-1127.

D. B. Rubin, J. L. Schafer, and N. Schenker. 1988. Imputation strategies for missing values in post-enumeration surveys. Survey Methodology 14: 209-221.

Last updated: May 21, 2003