Research

  • Applied machine learning
  • Biostatistics and bioinformatics
  • Functional data
  • Quantitative image analysis
  • Robust and semi-parametric statistical methods

Research Support

NSF  National Science Foundation

Google Scholar Profile

Publications

  1. Zuo J, Simpson DG, O’Brien WD Jr., McFarlin BL, Han A. (2024). Automated field of interest determination for quantitative ultrasound analyses of cervical tissues in spontaneous preterm birth risk assessment. Ultrasound in Medicine and Biology, 50(12), 1861-1867. https://doi.org/10.1016/j.ultrasmedbio.2024.08.011
  2. Villegas-Downs M, Mohammadi M, Han A, O’Brien WD Jr., Simpson DG, Peters TA, Schlaeger JM, McFarlin BL. (2024). Trajectory of postpartum cervical remodeling in women delivering full-term and spontaneous preterm: sensitivity to quantitative ultrasound biomarkers. Ultrasound in Medicine and Biology. 50(12), 1777-1784. https://doi.org/10.1016/j.ultrasmedbio.2024.06.015.
  3. McFarlin BL, Villegas-Downs M, Mohammadi M, Han A, Simpson DG, O’Brien WD Jr. (2024). Enhanced identification of at-risk women for preterm birth via quantitative ultrasound: A prospective cohort study. American Journal of Obstetrics & Gynecology Maternal Fetal Medicine MFM, 6(5), Article 101250. https://doi.org/10.1016/j.ajogmf.2023.101250.
  4. Park Y, Han K, Simpson DG (2023). Testing linear operator constraints in functional response regression with incomplete response functions. Electronic Journal of Statistics 2023, Vol. 17, No. 2, 3143-3180. PMCID: PMC11299897.
  5. Li B, Simpson DG (2023). Reflections on the IDEA Forum – Statistics, Climate Change, and Sustainability. Chance, Vol. 36, No. 1, pp. 25-30. Online.
  6. McFarlin BL, Liu Y, Villegas-Downs M, Mohammadi M, Simpson DG, Han A, O’Brien WD (2023). Predicting spontaneous preterm birth risk is improved when quantitative ultrasound data are included with historical clinical data. Ultrasound in Medicine & Biology, Vol. 49, pp. 1145-1152. https://doi.org/10.1016/j.ultrasmedbio.2022.12.018.
  7. Park Y, Chen X, Simpson DG (2022). Robust inference for partially observed functional response data. Statistica Sinica, Vol. 32, pp. 2265-2293. DOI: https://doi.org/10.5705/ss.202020.0358. PMID:36353392.
  8. Menictas M, Nolan TH, Simpson DG, Wand MP (2021). Streamlined Variational Inference for Higher Level Group-Specific Curve Models. Statistical Modelling. Vol. 21, pp. 479-519. DOI: 10.1177/1471082X20930894.  [arXiv]
  9. Erickson-Bhatt SJ, Simpson DG, Boppart, SA. (2020). Statistical evaluation of reader variability in assessing the diagnostic performance of optical coherence tomography. Journal of Biomedical Optics. Vol. 25(11), 116002, https://doi.org/10.1117/1.JBO.25.11.116002.
  10. Park Y, Simpson DG. (2019). Robust probabilistic classification applicable to irregularly sampled functional data. Computational Statistics & Data Analysis. Vol. 131, pp.37-49 .  DOI: 10.1016/j.csda.2018.08.001.  PubMed: PMC6510497
  11. Chen S, McFarlin BL, Meagher BT, Peters TA, Simpson DG, O’Brien WD, & Han A (2019). Repeatability and reproducibility of a clinically based QUS phantom study for preterm birth prediction.. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 66(9), 1413-1421. https://doi.org/10.1109/TUFFC.2019.2921925
  12. Nolan R, Adie SG, Marjanovic M, Chaney EJ, South FA, Monroy GL, Shemonski ND, Erickson-Bhatt SJ, Shelton RL, Bower AJ, Simpson DG, Cradock KA, Liu ZG, Ray PS, Boppart SA. (2016). Intraoperative optical coherence tomography for assessing human lymph nodes for metastatic cancer. BMC Cancer 16:144. https://doi.org/10.1186/s12885-016-2194-4.
  13. Marjanovic, M., Nolan, RM, Erickson-Bhatt, SJ, Adie, SG, Chaney, EJ, South, FA, Monroy GL, Shemonski ND, Shelton RL, Bower AJ, Simpson DG, Ray PS, Cradock KA, Liu ZG, Boppart SA (2016). Intraoperative in vivo assessment of lymph nodes with optical coherence tomography. In Clinical and Translational Biophotonics, Translational 2016 OSA – The Optical Society. https://doi.org/10.1364/TRANSLATIONAL.2016.TM4B.3
  14. McFarlin BL, Kumar V, Bigelow TA, Simpson DG, White-Traut RC, Abramawicz JS, O’Brien WD. (2015). Beyond Cervical Length: A pilot study of ultrasonic attenuation for early detection of preterm birth risk. Ultrasound in Medicine and Biology,  Vol. 41, No. 11,  pp. 3023-3029.  Online
  15. Wirtzfeld LA, Ghoshal G, Rosado-Mendez IM, Nam K, Park Y, Pawlicki AD, Miller RJ, Simpson DG, Zagzebski JA, Oelze ML, Hall TJ, O’Brien WD. (2015). Quantitative ultrasound comparison of MAT and 4T1 mammary tumors in mice and rats across multiple imaging systems. Journal of Ultrasound in Medicine, Vol. 34, pp. 1373-1383. PubMed
  16. Smith BW, Simpson DG, Sarwate S, Miller RJ, Erdman JW, O’Brien WD. (2015). Contrast ultrasound imaging of the aorta does not affect progression of atherosclerosis or cardiovascular biomarkers in ApoE-/- mice. Journal of Ultrasound in Medicine, Vol. 34, pp. 1115-1122. PubMed
  17. Smith BW, Simpson DG, Miller RJ, Erdman JW, O’Brien WD. (2015). Contrast ultrasound imaging does not affect Hsp 70 expression in cholesterol-fed rabbit aorta. Journal of Ultrasound in Medicine, Vol. 34(7), pp. 1209-1216. PubMed
  18. Han A, Erdman JW, Simpson DG, Andre MP, O’Brien WD. (2014). Early Detection of Fatty Liver Disease in Mice via Quantitative Ultrasound. Proceedings of the 2014 IEEE Ultrasonics Symposium, pp 2363-2366. PDF
  19. Wirtzfeld LA, Nam K, Labyed Y, Ghoshal G, Haak A, Sen-Gupta E, He Z, Hirtz NR, Miller RJ, Sarwate S, Simpson DG, Zagzebski JA, Bigelow TA, Oelze ML, Hall TJ, O’Brien WD. (2013). Techniques and evaluation from a cross-platform imaging comparison of quantitative ultrasound parameters in an in vivo rodent fibroadenoma model. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. Vol. 60, 1386-1400. PDF
  20. Imrey PB, Simpson DG (2012). Categorical data. In: Encyclopedia of Environmetrics, Second Edition. Wiley, New York. In press.
  21. Yang Y, Simpson DG. (2012). Conditional decomposition diagnostics for regression analysis of zero-inflated and left-censored data. Statistical Methods in Medical Research, August 2012 21:379-392. PDF
  22. Smith BW, Simpson DG, Sarwate S, Miller RJ, Blue JP, Haak A, O’Brien WD, Erdman JW (2012). Contrast ultrasound imaging of the aorta alters vascular morphology and circulating von Willebrand Factor in hypercholesterolemic rabbits. Journal of Ultrasound in Medicine, 31, 711-720. PMID: 22535718 PDF
  23. Wirtzfeld LA, Ghoshal G, Hafez ZT, Nam K, Labyed Y, Anderson JJ, Herd M-T, Haak A, He Z, Miller RJ, Sarwate S, Simpson DG, Zagzebski JA, Bigelow TA, Oelze ML, Hall TJ, O’Brien WD. (2010). Cross-imaging platform comparison of ultrasonic backscatter coefficient measurements of live rat tumors. Journal of Ultrasound in Medicine, Vol. 29, pp. 1117-1123. PDF
  24. Yang Y, Simpson DG (2010). Unified computational methods for regression analysis of zero-inflated and bound-inflated data. Computational Statistics and Data Analysis. Vol. 54, pp.1525-1534. PDF
  25. O’Brien WD, Yang Y, Simpson DG (2009). Threshold estimation and superthreshold behavior of ultrasound-induced lung hemorrhage in rats: role of age dependency. Ultrasound in Medicine and Biology. 35, 129-135. PDF
  26. Xie M, Simpson DG, Carroll RJ (2008). Semiparametric analysis of heterogeneous data using varying-scale generalized linear models. Journal of the American Statistical Association. Vol. 103, pp.650-660. PDF
  27. Fowlkes JB, Abramowicz JS, Church CC, Holland CK, Miller DL, O’Brien Jr. WD, Sanghvi NT, Stratmeyer ME, Zachary JF, Deng CX, Harris GR, Herman BA, Hynynen KH, Merritt CRB, Thomenius KE, Bailey MR, Carson PL, Carstensen EL, Frizzell LA, Nyborg WL, Barnett SB, Duck FA, Edmonds PD, Ziskin MC, Abbott JG, Dalecki D, Dunn F, Greenleaf JF, Salvesen KA, Siddiqi TA, Averkiou MA, Brayman AA, Everbach EC, Wible Jr. JH, Wu J, Simpson DG (2008). American Institute of Ultrasound in Medicine consensus report on potential bioeffects of diagnostic ultrasound: Executive summary. Journal of Ultrasound in Medicine, 27, pp. 503 – 515.
  28. O’Brien WD, Yang Y, Simpson DG, Frizzell LA, Miller RJ, Blue JP, Zachary JF (2006). Threshold estimates of ultrasound-induced lung hemorrhage in adult rabbits, and comparison of thresholds in mice, rats, rabbits and pigs. Ultrasound in Medicine and Biology. Vol 32, pp.1793-1804. PDF
  29. O’Brien WD, Simpson DG, Frizzell LA, Zachary JF (2006). Superthreshold behavior of ultrasound-induced lung hemorrhage in adult rats: role of pulse repetition frequency and pulse duration. Journal of Ultrasound in Medicine, Vol. 25, pp.873-882. PDF
  30. O’Brien WD, Simpson DG, Frizzell LA, Zachary JF (2005). Superthreshold behavior of ultrasound-induced lung hemorrhage in adult rats: role of pulse repetition frequency and exposure duration revisited. Journal of Ultrasound in Medicine. Vol. 24, pp.339-348. PDF
  31. Simpson DG, Ho M, Yang Y, Zhou J, Zachary JF, O’Brien WD (2004). Excess Risk Thresholds in Ultrasound Safety Studies: Statistical Methods for Data on Occurrence and Size of Lesions. Ultrasound in Medicine and Biology. Vol. 30, pp. 1289-1295. PDF
  32. O’Brien WD, Yang Y, Simpson DG (2004). Evaluation of unscanned-mode soft-tissue thermal index for rectangular sources. Ultrasound in Medicine and Biology. Vol. 30, pp. 965-972. PDF
  33. O’Brien WD, Simpson DG, Frizzell LA, Zachary, JF (2004). Effect of contrast agent on the incidence and magnitude of ultrasound-induced lung hemorrhage in rats. Echocardiography. Vol. 21, pp. 417-422. PDF
  34. Kim TY, Kim D, Park BU, Simpson DG (2004). Nonparametric detection of correlated errors. Biometrika. 91, 491-496. JSTOR
  35. He X, Cui H, Simpson DG (2004). Longitudinal data analysis using t-type regression. Journal of Statistical Planning and Inference. Vol. 122, 253-269. Invited for volume in honor of J.W. Tukey. Online
  36. O’Brien WD, Simpson DG, Frizzell LA, Zachary JF (2003). Threshold estimates and superthreshold behavior of ultrasound-induced lung hemorrhage in adult rats: Role of pulse duration. Ultrasound in Medicine and Biology. 29, 1625-1634. PDF
  37. O’Brien WD, Simpson DG, Ho M, Miller RJ, Frizzell LA, Zachary JF (2003). Superthreshold behavior and threshold estimation of ultrasound-induced lung hemorrhage in pigs: Role of age dependency. IEEE Transactions on Ultrasound, Ferroelectrics, and Frequency Control. 50, 153-169. PDF
  38. Simpson DG (2002). Comment on “Nearest Neighbor Variance Estimation (NNVE): Robust Covariance Estimation via Nearest Neighbor Cleaning.” Journal of the American Statistical Association. 97, 1015. Invited comment.
  39. Fu L, Simpson DG (2002). Conditional risk models for ordinal response data: Simultaneous logistic regression analysis and generalized score tests. Journal of Statistical Planning and Inference. 108, 201-217. Invited for Volume in honor of C.R. Rao. Online
  40. O’Brien WD, Simpson DG, Frizzell LA, Zachary JF (2001). Superthreshold behavior and threshold estimates of ultrasound-induced lung hemorrhage in adult rats: role of beamwidth. IEEE Transactions on Ultrasonics. Ferroelectrics, and Frequency Control. 48, 1695-1705. PDF
  41. Imrey PB, Simpson DG (2001). Categorical data. In: Encyclopedia of Environmetrics. Wiley, New York.
  42. Simpson DG (2001). Ordinal response. In: Encyclopedia of Environmetrics. Wiley, New York.
  43. Zhou H, Xie M, Simpson DG, Weinberg CR (2001). A generalized likelihood ratio approach for cluster-correlated data from human fertility studies. Sankhya, Series B, Vol. 63, pp. 56-68. JSTOR
  44. Zachary JF, Sempsrott JM, Frizzell LA, Simpson DG, O’Brien WD (2001). Superthreshold behavior and threshold estimation of ultrasound-induced lung hemorrhage in adult mice and rats. IEEE Transactions on Ultrasonics. Ferroelectrics, and Frequency Control. 48, 581-592. PDF
  45. He X, Simpson DG, Wang G (2000). Breakdown points of t-type regression estimators. Biometrika, 87, 675-687. JSTOR
  46. Simpson DG, Imrey P, Geling O, Butkus S (2000). Statistical estimation of child abuse rates from administrative databases. Children and Youth Services Review, 22, 951-971. PDF
  47. Xie M, Simpson DG, Carroll, RJ (2000). Random effects in interval-censored ordinal regression: latent structure and Bayesian approach. Biometrics, 56, 376-383. JSTOR
  48. Chen H-S, Simpson DG, Ying Z (2000). Infill asymptotics for a stochastic process model with measurement error. Statistica Sinica, 10, 141-156. PDF
  49. Locantore N, Marron JS, Simpson DG, Tripoli N, Zhang JT, Cohen KL  (1999). Robust principal component analysis for functional data (with discussion). Test, 8, 1-73. PS
  50. Xie M, Simpson DG (1999). Regression modeling of ordinal data with nonzero baselines. Biometrics, 55, 308-316. JSTOR
  51. Xie M, Simpson DG (1998). Categorical exposure-response regression analysis of toxicology experiments. In Case Studies in Environmental Statistics, Ed. D. Nychka, W.W. Piegorsch and L.H. Cox. Lecture Notes in Statistics 132. Springer, p. 121-141. PDF
  52. Simpson DG, Yohai VJ (1998). Functional stability of one-step GM-estimators in approximately linear regression. The Annals of Statistics, 26, 1147-1169. JSTOR
  53. Simpson DG, He X, Liu YT (1998). Comment on “Edge-Preserving Smoothers for Image Processing.” Journal of the American Statistical Association, 93, 544-548. JSTOR
  54. Ge N, Simpson DG (1998). Correlation and high dimensional consistency in pattern recognition. Journal of the American Statistical Association, 93, 995-1006. JSTOR
  55. Xie M, Simpson DG, Carroll RJ (1997). Scaled link functions for heterogeneous ordinal response data. In Modelling Longitudinal and Spatially Correlated Data: Methods, Applications and Future Directions, Ed. T. Gregoire, Springer-Verlag, Lecture Notes in Statistics, p. 23-36. PDF
  56. Guth DL, Carroll RJ, Simpson DG, Zhou H (1997). Categorical regression analysis of acute inhalation exposure to tetrachloroethylene.  Risk Analysis, 17, 321-332. Online
  57. Simpson DG (1997). Introduction to Rousseeuw (1984), “Least Median of Squares Regression,” in Breakthroughs in Statistics, Volume III, Ed. by S. Kotz and N.L. Johnson, New York: Springer-Verlag, pp. 433-439.
  58. Simpson DG (1997). Remarks on environmental data archives and their use in monitoring the US Mexico border area. Chemometrics and Intelligent Laboratory Systems, 37, 113-114.
  59. Simpson DG, Chang YC (1997). Reweighting approximate GM estimators: asymptotics and residual-based graphics. Journal of Statistical Planning and Inference, 57(2), 273-294. Invited. Online
  60. Simpson DG, Carroll RJ, Xie M, Guth DL (1996). Weighted logistic regression and robust analysis of diverse toxicology data. Communications in Statistics, Theory and Methods, 25, 2615-2632. Invited.
  61. Simpson DG, Carroll RJ, Zhou H, Guth DL (1996). Interval censoring and marginal analysis in ordinal regression. Journal of Agricultural, Biological and Environmental Statistics, 1, 354-376. JSTOR
  62. Eubank RL, Hart JD, Simpson DG, Stefanski LA (1995). Testing for additivity in nonparametric regression. The Annals of Statistics, 23, 1896-1920. JSTOR
  63. Simpson DG (1993). Review of L1-Statistical Analysis and Related Methods, Edited by Y. Dodge. Journal of the American Statistical Association, 88, 1172.
  64. He X, Simpson DG (1993). Lower bounds for contamination bias: Globally minimax versus locally linear estimation. The Annals of Statistics, 21, 314-337. JSTOR
  65. Bietz J, Simpson DG (1992). Electrophoresis and chromatography of wheat proteins: available methods, and procedures for statistical evaluation of the data. Journal of Chromatography, 624, 53-80. Invited. Online
  66. Simpson DG, Ruppert D, Carroll RJ (1992). On one-step GM-estimates and stability of inferences in linear regression. Journal of the American Statistical Association 87, 439-450. JSTOR
  67. He X, Simpson DG (1992). Robust direction estimation. The Annals of Statistics 20, 351-369. JSTOR
  68. Simpson DG (1991). Review of The Statistical Analysis of Discrete Data, by T. J. Santner and D. E. Duffy. Technometrics 33, 258-259.
  69. Simpson DG, Guo S, Sacks J, Bietz JA, Huebner F, Nelson T (1991). Relating chromatographic data to measurements of wheat quality: case studies in dimension reduction. Chemometrics and Intelligent Laboratory Systems 10, 155-167. Online
  70. Bietz JA, Huebner F, Nelson T, Simpson DG, Guo S, Sacks J (1991). Statistical interpretation of data from high-performance liquid chromatography of wheat proteins. In: Bushuk, W., and Tkachuk, R. (eds.) Gluten Proteins 1990 (Int. Workshop), 4th, pp.420-432.
  71. Ruppert, D, Simpson, DG (1990). Comments on `Unmasking multivariate outliers and leverage points.’ Journal of the American Statistical Association 85, 644-646. JSTOR
  72. He X, Simpson DG,  Portnoy, S (1990). Breakdown robustness of tests. Journal of the American Statistical Association 85, 446-452. JSTOR
  73. Simpson DG, Margolin BH (1990). Nonparametric testing for dose-response curves subject to downturns: asymptotic power considerations. The Annals of Statistics 18, 373-390. JSTOR
  74. Simpson DG (1989). Hellinger deviance tests: efficiency, breakdown points, and examples.  Journal of the American Statistical Association 84, 107-113. JSTOR
  75. Simpson DG, Dallal GE (1989). BUMP: a FORTRAN program for identifying dose-response curves subject to downturns. Computers and Biomedical Research 22, 36-43. Online
  76. Simpson DG (1987). Minimum Hellinger distance estimation for the analysis of count data. Journal of the American Statistical Association 82, 802-807. JSTOR
  77. Simpson DG, Carroll RJ, Ruppert, D (1987). M-estimation for discrete data: asymptotic distribution theory and implications. The Annals of Statistics 15, 657-669. JSTOR
  78. Simpson DG, Margolin BH (1986). Recursive nonparametric testing for dose-response relationships subject to downturns at high doses. Biometrika 73, 589-596. JSTOR

Professor, Department of Statistics