Faculty Affiliates

A. James O'Malley, PhD

Professor of Biostatistics, Department of Biomedical Data Science, The Dartmouth Institute for Health Policy and Clinical Practice

Bayesian Methods; Social Network Analysis; Causal Inference; Multivariate-Multilevel Models

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A. James O'Malley, PhD
Professor of Biostatistics, Department of Biomedical Data Science, The Dartmouth Institute for Health Policy and Clinical Practice

Dr. O’Malley’s methodological research interests have centered on social network analysis, causal inference (comparative effectiveness research), multivariate-hierarchical modeling, and previously the design and analysis of medical device clinical trials. In these, he has developed novel statistical methods, often involving novel use of Bayesian statistical methods, to solve important methodological and applied problems in health policy and health services research, including the evaluation of treatments and outcomes of health care in multiple areas of medicine. This has led to advances in interventional cardiology, vascular surgery, measuring quality of health care, mental health and long-term care.

Dr. O’Malley’s primary teaching activities currently include teaching a statistics class to medical and health policy students, guest lectures in other courses, and presenting short courses at conferences and other forums. His educational activities also include a large number of invited seminars; mentoring colleagues, post-doctoral fellows and students; and service to the statistics profession. In addition, Dr. O’Malley’s service to the statistics profession includes eight-years at the forefront of the Health Policy Statistics Section of the ASA, associate editorships at both Statistics in Medicine and Health Services and Outcomes Research Methodology, and as reviewer for over 20 respected academic journals.

In recognition of many of the above contributions, Dr. O’Malley was elected fellow of the American Statistical Association (ASA) in 2012 and awarded the 2011 Mid-Career Award by the Health Policy Statistics Section of the ASA (a single award is given biannually).

For fun, he enjoys several sports and particularly tennis, swimming, road biking, and trail running. Since moving to the Upper Valley, he has enjoyed improving his downhill and cross-country skiing.

Selected Publications

O'Malley AJ, Park S. A novel cluster sampling design that couples multiple surveys to support multiple inferential objectives. Health Serv Outcomes Res Methodol. 2020 Sep;20(2-3):85-110. doi: 10.1007/s10742-020-00210-y. PMID: 33613088; PMCID: PMC7888270.
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Levy JJ, O'Malley AJ. Don't dismiss logistic regression: The case for sensible extraction of interactions in the era of machine learning. BMC Med Res Methodol. 2020 Jun 29;20(1):171. doi: 10.1186/s12874-020-01046-3. PMID: 32600277; PMCID: PMC7325087.
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O'Malley AJ, Moen EL, Bynum JPW, Austin AM, Skinner JS. Modeling peer effect modification by network strength: The diffusion of implantable cardioverter defibrillators in the US hospital network. Stat Med. 2020 Apr 15;39(8):1125-1144. doi: 10.1002/sim.8466. PMID: 31925971.
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Moen EL, Bynum JP, Skinner JS, O'Malley AJ. Physician network position and patient outcomes following implantable cardioverter defibrillator therapy. Health Serv Res. 2019 Aug;54(4):880-889. doi: 10.1111/1475-6773.13151. PMID: 30937894; PMCID: PMC6606612.
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Ramkumar N, Martinez-Camblor P, Columbo JA, Osborne NH, Goodney PP, O'Malley AJ. Adverse events after atherectomy: Analyzing long-term outcomes of endovascular lower extremity revascularization techniques. J Am Heart Assoc. 2019 Jun 18;8(12):e012081. doi: 10.1161/JAHA.119.012081. PMID: 31165658; PMCID: PMC6645635.
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An C, O'Malley AJ, Rockmore DN. Towards intelligent complex networks: the space and prediction of information walks. Appl Netw Sci. 2019;4(1):35. doi: 10.1007/s41109-019-0140-5. PMID: 31259230; PMCID: PMC6565809.
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Huling JD, Yu M, O'Malley AJ. Instrumental variable based estimation under the semiparametric accelerated failure time model. Biometrics. 2019 Jun;75(2):516-527. doi: 10.1111/biom.12985. PMID: 30357822.
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O'Malley AJ, James P, MacKenzie TA, Byun J, Subramanian SV, Block JP. Modeling a bivariate residential-workplace neighborhood effect when estimating the effect of proximity to fast-food establishments on body mass index. Stat Med. 2019 Mar 15;38(6):1013-1035. doi: 10.1002/sim.8039. PMID: 30460712; PMCID: PMC6377346.
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Martinez-Camblor P, MacKenzie TA, Staiger DO, Goodney PP, O’Malley AJ. An instrumental variable procedure for estimating Cox models with non-proportional hazards in the presence of unmeasured confounding. Journal of the Royal Statistical Society, Series C (Applied Statistics). 2019, 985. doi: 10.1111/rssc.12341.
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Martínez-Camblor P, Mackenzie T, Staiger DO, Goodney PP, O'Malley AJ. Adjusting for bias introduced by instrumental variable estimation in the Cox proportional hazards model. Biostatistics. 2019 Jan 1;20(1):80-96. doi: 10.1093/biostatistics/kxx062. PMID: 29267847.
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Columbo JA, Martinez-Camblor P, MacKenzie TA, Staiger DO, Kang R, Goodney PP, O’Malley AJ. A comparative analysis of long-term mortality after carotid endarterectomy and carotid stenting. J Vasc Surg. 2019 Jan;69(1):104-109. doi: 10.1016/j.jvs.2018.03.432. PMID: 29914828; PMCID: PMC6295272.
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MacKenzie TA, O'Malley AJ, Bekelis K. Reporting of baseline characteristics to accompany analysis by instrumental variables. Epidemiology. 2018 Nov;29(6):817-820. doi: 10.1097/EDE.0000000000000914. PMID: 30188381; PMCID: PMC6362835.
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Bobak CA, Barr PJ, O'Malley AJ. Estimation of an inter-rater intra-class correlation coefficient that overcomes common assumption violations in the assessment of health measurement scales. BMC Med Res Methodol. 2018;18(1):93. Published 2018 Sep 12. doi:10.1186/s12874-018-0550-6
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Columbo JA, Martinez-Camblor P, MacKenzie TA, Staiger DO, Kang R, Goodney PP, O'Malley AJ. Comparing long-term mortality after carotid endarterectomy vs carotid stenting using a novel instrumental variable method for risk adjustment in observational time-to-event data. JAMA Netw Open. 2018 Sep 7;1(5):e181676. doi: 10.1001/jamanetworkopen.2018.1676. Erratum in: JAMA Netw Open. 2018 Oct 5;1(6):e184055. PMID: 30646140; PMCID: PMC6324509.
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An C, O'Malley AJ, Rockmore DN. Referral paths in the U.S. physician network. Appl Netw Sci. 2018;3(1):20. doi: 10.1007/s41109-018-0081-4. PMID: 30839747; PMCID: PMC6214314.
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Aschbrenner KA, Bobak C, Schneider EJ, Naslund JA, Brunette MF, O'Malley AJ. Egocentric social networks and smoking among adults with serious mental illness. Transl Behav Med. 2018 Jul 17;8(4):531-539. doi: 10.1093/tbm/ibx014. PMID: 30016519.
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Moen EL, Bynum JP, Austin AM, Skinner JS, Chakraborti G, O'Malley AJ. Assessing variation in implantable cardioverter defibrillator therapy guideline adherence with physician and hospital patient-sharing networks. Med Care. 2018 Apr;56(4):350-357. doi: 10.1097/MLR.0000000000000883. PMID: 29419707; PMCID: PMC5851832.
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An C, O'Malley AJ, Rockmore DN, Stock CD. Analysis of the U.S. patient referral network. Stat Med. 2018 Feb 28;37(5):847-866. doi: 10.1002/sim.7565. Epub 2017 Dec 4. PMID: 29205445; PMCID: PMC5799011.
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Landon BE, Keating NL, Onnela JP, Zaslavsky AM, Christakis NA, O'Malley AJ. Patient-sharing networks of physicians and health care utilization and spending among medicare beneficiaries. JAMA Intern Med. 2018 Jan 1;178(1):66-73. doi: 10.1001/jamainternmed.2017.5034. PMID: 29181504; PMCID: PMC5833496.
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Choi J, O’Malley AJ. Estimating the causal effect of treatment in observational studies with survival time endpoints and unmeasured confounding. Journal of the Royal Statistical Society, Series C (Applied Statistics), 2017, 66, 159-185. PMID: 30686843.
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Neelon B, O’Malley AJ, Smith VA. Modeling zero-modified count and semicontinuous data in health services research, part 2: Case studies. Statistics in Medicine, 2016, 35 (27), 5094-5112. doi: 10.1002/sim.7063. PMID: 27500973.
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Neelon B, O’Malley AJ, Smith VA. Modeling zero-modified count and semicontinuous data in health services research, part 1: Background and overview. Statistics in Medicine, 2016, 35 (27), 5070-5093. doi: 10.1002/sim.7050. PMID: 27500945.
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O’Malley AJ, Zaslavsky AM. Optimal small-area estimation and design when nonrespondents are subsampled for follow-up. Journal of Survey Statistics and Methodology. 2016 March; 4(1): p. 2–21.
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Moen EL, Fricano-Kugler CJ, Luikart BW, O'Malley AJ. Analyzing clustered data: Why and how to account for multiple observations nested within a study participant? PLoS One. 2016 Jan 14;11(1):e0146721. doi: 10.1371/journal.pone.0146721. PMID: 26766425; PMCID: PMC4713068.
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Moen EL, Austin AM, Bynum JP, Skinner JS, O’Malley AJ. An analysis of patient-sharing physician networks and implantable cardioverter defibrillator therapy. Health Services and Outcomes Research Methodology, 2016, 16, 132-153. PMID: 27597812.
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O'Malley AJ, Zelevinsky K, He Y, Busch AB. Do patients at sites with high RCT enrollment propensity have better outcomes? Med Care. 2015 Nov;53(11):989-95. doi: 10.1097/MLR.0000000000000429. PMID: 26465127; PMCID: PMC4672722.
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Busch AB, He Y, Zelevinsky K, O'Malley AJ. Predicting participation in psychiatric randomized controlled trials: Insights From the STEP-BD. Psychiatr Serv. 2015 Aug 1;66(8):817-23. doi: 10.1176/appi.ps.201300557. PMID: 25828873; PMCID: PMC4888778.
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O'Malley AJ, Paul S. Using retrospective sampling to estimate models of relationship status in large longitudinal social networks. Comput Stat Data Anal. 2015 Feb 1;82:35-46. doi: 10.1016/j.csda.2014.08.001. PMID: 26692600; PMCID: PMC4673682.
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O'Malley AJ, Elwert F, Rosenquist JN, Zaslavsky AM, Christakis NA. Estimating peer effects in longitudinal dyadic data using instrumental variables. Biometrics. 2014 Sep;70(3):506-15. doi: 10.1111/biom.12172. PMID: 24779654; PMCID: PMC4213357.
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MacKenzie TA, Tosteson TD, Morden NE, Stukel TA, O'Malley AJ. Using instrumental variables to estimate a Cox's proportional hazards regression subject to additive confounding. Health Serv Outcomes Res Methodol. 2014 Jun;14(1-2):54-68. doi: 10.1007/s10742-014-0117-x. PMID: 25506259; PMCID: PMC4261749.
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Paul S, O'Malley AJ. Hierarchical longitudinal models of relationships in social networks. J R Stat Soc Ser C Appl Stat. 2013 Oct;62(5):705-722. doi: 10.1111/rssc.12013. PMID: 24729637; PMCID: PMC3979311.
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O'Malley AJ. The analysis of social network data: an exciting frontier for statisticians. Stat Med. 2013 Feb 20;32(4):539-55. doi: 10.1002/sim.5630. PMID: 23023735; PMCID: PMC3553267.
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O'Malley AJ. Instrumental variable specifications and assumptions for longitudinal analysis of mental health cost offsets. Health Serv Outcomes Res Methodol. 2012 Dec;12(4):254-272. doi: 10.1007/s10742-012-0097-7. PMID: 23226968; PMCID: PMC3515775.
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O'Malley AJ, Cotterill P, Schermerhorn ML, Landon BE. Improving observational study estimates of treatment effects using joint modeling of selection effects and outcomes: The case of AAA repair. Med Care. 2011 Dec;49(12):1126-32. doi: 10.1097/MLR.0b013e3182363d64. PMID: 22011709; PMCID: PMC3979312.
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O'Malley AJ, Christakis NA. Longitudinal analysis of large social networks: Estimating the effect of health traits on changes in friendship ties. Stat Med. 2011 Apr 30;30(9):950-64. doi: 10.1002/sim.4190. PMID: 21287589; PMCID: PMC3079434.
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Neelon B, O'Malley AJ, Normand SL. A bayesian two-part latent class model for longitudinal medical expenditure data: Assessing the impact of mental health and substance abuse parity. Biometrics. 2011 Mar;67(1):280-9. doi: 10.1111/j.1541-0420.2010.01439.x. PMID: 20528856; PMCID: PMC4445417.
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O'Malley AJ, Marsden PV. The analysis of social networks. Health Serv Outcomes Res Methodol. 2008 Dec 1;8(4):222-269. doi: 10.1007/s10742-008-0041-z. PMID: 20046802; PMCID: PMC2799303.
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O’Malley AJ, Zaslavsky AM. Domain-level covariance analysis for multi-level survey data with structured nonresponse. Journal of the American Statistical Association. 2008 Dec; 103(484): p. 1405-418.
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O’Malley AJ, Zaslavsky AM. Variance-covariance functions for domain means of ordinal survey items. Survey Methodology. 2006; 31: p. 169-182.
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O'Malley AJ, Normand SL. Likelihood methods for treatment noncompliance and subsequent nonresponse in randomized trials. Biometrics. 2005 Jun;61(2):325-34. doi: 10.1111/j.1541-0420.2005.040313.x. PMID: 16011678.
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