Shyamal D. Peddada, Ph.D.

Shyamal D. Peddada, Ph.D.
Principal Investigator

Tel (919) 541-1122
Fax (919) 541-4311
peddada@niehs.nih.gov

Curriculum Vitae (peddada-cv09.pdf)   P.O. Box 12233
Mail Drop A3-03
Research Triangle Park, North Carolina 27709
Delivery Instructions

Shyamal Peddada directs the Statistical Consulting Service (SCS) offered by the Biostatistics Branch to researchers within the Division of Intramural Research (DIR).  In addition to using standard statistical methods for analyzing data, as needed, the SCS develops innovative statistical methods that are appropriate for analyzing data. The service works with researchers on study design and analysis of experiments and participates in the preparation of the National Toxicology Program’s technical report series on toxicity and carcinogenicity of various chemicals.  It also offers short courses on statistical design and analysis for DIR researchers.

Peddada also conducts methodological research in the field of order restricted inference with applications to toxicology and analysis of gene expression data.  He exploits the underlying inequality structure in the data, which generally results in an increased power in the analysis and better interpretation of the data.  The statistical methods that Peddada developed have a wide range of applications.  For instance, he has developed a new statistical procedure for analyzing NTP's rodent cancer bioassay data that takes into account NTP’s database of relevant historical control data.  He is also developing statistical methods for analyzing gene expression data obtained from time-course and dose-response microarray experiments. He recently developed free software called "Order Restricted Inference for Ordered Gene ExpressioN" (ORIOGEN) for analyzing gene expression data obtained from time-course/dose-response studies. ORIOGEN may be downloaded from the Biostatistics Branch Resources page.

Selected Publications

1. Peddada SD, and Richards D.  (1991). Proof of a Conjecture of M. L. Eaton on the Characteristic Function of the Wishart Distribution.  Annals of Probability, 19, 868-874.
2. Peddada SD, and Patwardhan G. (1992). Jackknife Variance Estimation in Linear Models. Biometrika, 79, 654-657.
3. Hwang JTG, and Peddada SD. (1994). Confidence Interval Estimation Subject to Order Restrictions. Annals of Statistics, 22, 67-93.
4. Peddada SD, and Chang TC. (1996).  Bootstrap Confidence Region Estimation of the Motion of Rigid Bodies. J. of Amer. Statist. Assoc., 81, 231-241.
5. Peddada SD, Prescott K, and Conaway M. (2001). Tests for Order Restrictions in Binary Data.  Biometrics, 57, 1219-1227.
6. Hoferkamp C, and Peddada SD. (2002).  Estimation of Parameters in Linear Models with Heteroscedastic Variances Subject to Order Restrictions.  J. Multivariate Analysis, 82, 65-87.
7. Peddada SD, Lobenhofer L, Li L, Afshari C, Weinberg C and Umbach D. (2003). Gene Selection and Clustering for Time-course and Dose-response Microarray Experiments using Order-restricted Inference. Bioinformatics, 19, 834-841.
8. Liu D, Umbach D, Peddada SD, Li L, Crockett P, and Weinberg C. (2004). A Random-Periods Model for Expression of Cell-Cycle Genes. Proc. of National Academy of Sci., 101, No. 19, 7240-7245.
9. Liu D, Weinberg C, and Peddada SD. (2004). A Geometric Approach to Determine Association and Coherence of the Activation Times of Cell-Cycling Genes under Different Experimental Conditions. Bioinformatics, 20, 2521-2528.
10. Peddada SD, Dinse G, and Haseman J. (2005). A Survival-adjusted Quantal Response Test for Comparing Tumor Incidence Rates.  J. Royal Statist. Soc., Ser – C, 54, 51-61.
11. Peddada SD, Dunson DB, and Tan X. (2005).  Estimation of Order-restricted Means from Correlated Data. Biometrika, 92, 703-715.
12. Peddada SD, Harris S, Zajd J, and Harvey E. (2005). ORIOGEN: Order Restricted Inference for Ordered Gene Expression Data.  Bioinformatics, 21, 3933-3934.
13. Peddada SD, and Kissling G. (2005). A Survival-Adjusted Quantal-Response Test for Analysis of Tumor Incidence Rates in Animal Carcinogenicity Studies. Env. Health Persp., 114, 537-541.
14. Peddada SD, Haseman J, Tan X, and Travlos G. (2006). Tests for Simple Tree Order Restriction with Application to Dose-response Studies. J. Royal Statist. Soc., Ser - C,55, 493-506.
15. Peddada SD, Dinse G, and Kissling G. (2007). Incorporating Historical Control Data When Comparing Tumor Incidence Rates. J. Amer. Stat. Assoc., 102, 1212-1220.
16. Guo W, and Peddada SD. (2008). Adaptive Choice of the Number of Bootstrap Samples in Large Scale Multiple Testing. Statistical Applications in Genetics and Molecular Biology, 7 (1), Art. 13.
17. Peddada SD, Laughlin S, Miner K, Guyon JP, Haneke K, Vahdat H, Semelka R, Kowalik A, Armao D, Davis B, and Baird D. (2008). Growth of Uterine Leiomyomata Among Pre-menopausal Black and White Women. Proc. of National Academy of Sci., 105, 19887-19892.
18. Rueda C Temprano M, and Peddada SD. (2008). Estimation of Parameters Subject to Order Restriction on a Circle with Application to Estimation of Phase Angles of Cell-Cycle Genes. J. Amer. Statist. Assoc., 104, 338-347.
19. Dunson DB, and Peddada SD. (2008). Bayesian nonparametric inference on stochastic ordering. Biometrika 95(4):859-874.
20. Guo W, Sarkar S, and Peddada SD. (2009). Controlling False Discoveries in Multidimensional Directional Decisions, with Applications to Gene Expression Data on Ordered Categories.Biometrics (in press).
21. Scott GJ, Ray MK, Ward T, McCann K, Peddada SD, Jiang FX, and Mishina Y. (2009). Abnormal glucose metabolism in heterozygous mutant mice for a type 1 receptor required For BMP signaling. Genesis (New York, N.Y.: 2000) 47(6), 385-391.

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