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Nima Hejazi, Ph.D.

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Biography
NSF Mathematical Sciences Postdoctoral Research Fellowship, New York, NY, USAPostdoctoral Fellowship06/2022Biostatistics, Causal Inference, Machine Learning
University of California, Berkeley, Berkeley, CA, USAPhD08/2021Biostatistics
University of California, Berkeley, Berkeley, CA, USABA12/2015Molecular & Cell Biology, Psychology, Public Health
2021 - 2022
Mathematical Sciences Postdoctoral Research Fellowship
2019
Tom Ten Have Memorial Award (for "exceptionally creative or skillful research in causal inference")
2020
The Wallace Lowe Fellowship
2019
The Eki & Nobuta Akahoshi and Seiko Baba Brodbeck Endowed Fund Scholarship
2018
The Wellness Scholarship in Honor of Chin Long Chiang

Overview
Dr. Hejazi's research interests combine modern causal inference and statistical machine learning focusing on the development of innovative methods for statistical inference within a model-agnostic framework. This results in novel techniques that are (1) robust, by leveraging data-adaptive and flexible estimation procedures; (2) efficient (i.e., attaining minimal variance), by using cutting-edge non-/semi-parametric efficiency theory; and (3) assumption-lean, by incorporating current scientific knowledge while respecting its many limitations. His approach to developing statistical methodology emphasizes a problem-first translational philosophy -- that inferential techniques should be tailored to specific issues arising in scientific collaborations so that these new methods speak most directly and clearly to the underlying questions. Dr. Hejazi is usually, but not exclusively, motivated by topics from distribution-free (nonparametric) inference, semiparametric-efficient inference, high-dimensional inference, (targeted) minimum loss-based estimation, biased sampling procedures (e.g., outcome-dependent two-phase designs, capture-recapture), and adaptive experimental design (e.g., adaptive group-sequential designs for finding optimal sequentially adaptive treatments). Most often, he studies these topics through the lens of particular causal inference problems (e.g., heterogeneous treatment effects, dose-response curve estimation, mediation analysis). Dr. Hejazi is also deeply interested in high-performance statistical computing and is a passionate advocate of open-source software for the promotion of transparency, reproducibility, and "data analytic hygiene" in the practice of applied statistics and statistical data science.

Dr. Hejazi's substantive scientific interests across the biomedical and public health sciences are diverse -- accordingly, over the years, he has contributed to scientific collaborations across a broad array of disciplines, including in molecular and environmental toxicology, large-scale interventional nutritional epidemiology, comparative (health) effectiveness research, studies using electronic health/medical records, and computational/high-dimensional biology. Most recently, he has been captivated by the rich statistical issues and pressing public health challenges often found in clinical trials or observational studies seeking to evaluate the efficacy of preventive vaccines or curative treatments of high-burden and/or neglected infectious diseases (HIV-1/AIDS, COVID-19, malaria) and in infectious disease epidemiology (especially in the design of optimal minimally invasive surveillance strategies).

"Far better an approximate answer to the right question, which is often vague, than the exact answer to the wrong question, which can always be made precise." --John Tukey

"Everyone is sure of this [that errors are normally distributed]...since the experimentalists believe that it is a mathematical theorem, and the mathematicians that it is an experimentally determined fact." --Henri Poincare

Featured Content

Bibliographic
Publications listed below are automatically derived from MEDLINE/PubMed and other sources, which might result in incorrect or missing publications. Faculty can login to make corrections and additions.
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PMC Citations indicate the number of times the publication was cited by articles in PubMed Central, and the Altmetric score represents citations in news articles and social media. (Note that publications are often cited in additional ways that are not shown here.) Fields are based on how the National Library of Medicine (NLM) classifies the publication's journal and might not represent the specific topic of the publication. Translation tags are based on the publication type and the MeSH terms NLM assigns to the publication. Some publications (especially newer ones and publications not in PubMed) might not yet be assigned Field or Translation tags.) Click a Field or Translation tag to filter the publications.
  1. Fong Y, McDermott AB, Benkeser D, Roels S, Stieh DJ, Vandebosch A, Le Gars M, Van Roey GA, Houchens CR, Martins K, Jayashankar L, Castellino F, Amoa-Awua O, Basappa M, Flach B, Lin BC, Moore C, Naisan M, Naqvi M, Narpala S, O'Connell S, Mueller A, Serebryannyy L, Castro M, Wang J, Petropoulos CJ, Luedtke A, Hyrien O, Lu Y, Yu C, Borate B, van der Laan LWP, Hejazi NS, Kenny A, Carone M, Wolfe DN, Sadoff J, Gray GE, Grinsztejn B, Goepfert PA, Little SJ, Paiva de Sousa L, Maboa R, Randhawa AK, Andrasik MP, Hendriks J, Truyers C, Struyf F, Schuitemaker H, Douoguih M, Kublin JG, Corey L, Neuzil KM, Carpp LN, Follmann D, Gilbert PB, Koup RA, Donis RO. Immune correlates analysis of the ENSEMBLE single Ad26.COV2.S dose vaccine efficacy clinical trial. Nat Microbiol. 2022 Nov 10. PMID: 36357712.
    Citations:    Fields:    
  2. Ertefaie A, Hejazi NS, van der Laan MJ. Nonparametric inverse-probability-weighted estimators based on the highly adaptive lasso. Biometrics. 2022 Jul 15. PMID: 35839293.
    Citations:    Fields:    
  3. Fong Y, McDermott AB, Benkeser D, Roels S, Stieh DJ, Vandebosch A, Gars ML, Van Roey GA, Houchens CR, Martins K, Jayashankar L, Castellino F, Amoa-Awua O, Basappa M, Flach B, Lin BC, Moore C, Naisan M, Naqvi M, Narpala S, O'Connell S, Mueller A, Serebryannyy L, Castro M, Wang J, Petropoulos CJ, Luedtke A, Hyrien O, Lu Y, Yu C, Borate B, van der Laan LWP, Hejazi NS, Kenny A, Carone M, Wolfe DN, Sadoff J, Gray GE, Grinsztejn B, Goepfert PA, Little SJ, de Sousa LP, Maboa R, Randhawa AK, Andrasik MP, Hendriks J, Truyers C, Struyf F, Schuitemaker H, Douoguih M, Kublin JG, Corey L, Neuzil KM, Carpp LN, Follmann D, Gilbert PB, Koup RA, Donis RO. Immune Correlates Analysis of a Single Ad26.COV2.S Dose in the ENSEMBLE COVID-19 Vaccine Efficacy Clinical Trial. medRxiv. 2022 Apr 12. PMID: 35441174; PMCID: PMC9016647.
    Citations:    
  4. Li H, Rosete S, Coyle J, Phillips RV, Hejazi NS, Malenica I, Arnold BF, Benjamin-Chung J, Mertens A, Colford JM, van der Laan MJ, Hubbard AE. Evaluating the robustness of targeted maximum likelihood estimators via realistic simulations in nutrition intervention trials. Stat Med. 2022 05 30; 41(12):2132-2165. PMID: 35172378.
    Citations: 1     Fields:    Translation:Humans
  5. Hejazi NS, Rudolph KE, Van Der Laan MJ, Díaz I. Nonparametric causal mediation analysis for stochastic interventional (in)direct effects. Biostatistics. 2022 Feb 01. PMID: 35102366.
    Citations:    Fields:    
  6. Amato HK, Hemlock C, Andrejko KL, Smith AR, Hejazi NS, Hubbard AE, Verma SC, Adhikari RK, Pokhrel D, Smith K, Graham JP, Pokhrel A. Biodigester Cookstove Interventions and Child Diarrhea in Semirural Nepal: A Causal Analysis of Daily Observations. Environ Health Perspect. 2022 01; 130(1):17002. PMID: 34985305.
    Citations:    Fields:    Translation:HumansPHPublic Health
  7. Gilbert PB, Montefiori DC, McDermott AB, Fong Y, Benkeser D, Deng W, Zhou H, Houchens CR, Martins K, Jayashankar L, Castellino F, Flach B, Lin BC, O'Connell S, McDanal C, Eaton A, Sarzotti-Kelsoe M, Lu Y, Yu C, Borate B, van der Laan LWP, Hejazi NS, Huynh C, Miller J, El Sahly HM, Baden LR, Baron M, De La Cruz L, Gay C, Kalams S, Kelley CF, Andrasik MP, Kublin JG, Corey L, Neuzil KM, Carpp LN, Pajon R, Follmann D, Donis RO, Koup RA. Immune correlates analysis of the mRNA-1273 COVID-19 vaccine efficacy clinical trial. Science. 2022 Jan 07; 375(6576):43-50. PMID: 34812653; PMCID: PMC9017870.
    Citations: 169     Fields:    Translation:HumansCells
  8. Gilbert PB, Montefiori DC, McDermott A, Fong Y, Benkeser D, Deng W, Zhou H, Houchens CR, Martins K, Jayashankar L, Castellino F, Flach B, Lin BC, O'Connell S, McDanal C, Eaton A, Sarzotti-Kelsoe M, Lu Y, Yu C, Borate B, van der Laan LWP, Hejazi N, Huynh C, Miller J, El Sahly HM, Baden LR, Baron M, De La Cruz L, Gay C, Kalams S, Kelley CF, Kutner M, Andrasik MP, Kublin JG, Corey L, Neuzil KM, Carpp LN, Pajon R, Follmann D, Donis RO, Koup RA. Immune Correlates Analysis of the mRNA-1273 COVID-19 Vaccine Efficacy Trial. medRxiv. 2021 Aug 15. PMID: 34401888.
    Citations:    
  9. Gray GE, Bekker LG, Laher F, Malahleha M, Allen M, Moodie Z, Grunenberg N, Huang Y, Grove D, Prigmore B, Kee JJ, Benkeser D, Hural J, Innes C, Lazarus E, Meintjes G, Naicker N, Kalonji D, Nchabeleng M, Sebe M, Singh N, Kotze P, Kassim S, Dubula T, Naicker V, Brumskine W, Ncayiya CN, Ward AM, Garrett N, Kistnasami G, Gaffoor Z, Selepe P, Makhoba PB, Mathebula MP, Mda P, Adonis T, Mapetla KS, Modibedi B, Philip T, Kobane G, Bentley C, Ramirez S, Takuva S, Jones M, Sikhosana M, Atujuna M, Andrasik M, Hejazi NS, Puren A, Wiesner L, Phogat S, Diaz Granados C, Koutsoukos M, Van Der Meeren O, Barnett SW, Kanesa-Thasan N, Kublin JG, McElrath MJ, Gilbert PB, Janes H, Corey L. Vaccine Efficacy of ALVAC-HIV and Bivalent Subtype C gp120-MF59 in Adults. N Engl J Med. 2021 03 25; 384(12):1089-1100. PMID: 33761206; PMCID: PMC7888373.
    Citations: 39     Fields:    Translation:HumansCellsCTClinical Trials
  10. Rudolph KE, Díaz I, Hejazi NS, van der Laan MJ, Luo SX, Shulman M, Campbell A, Rotrosen J, Nunes EV. Explaining differential effects of medication for opioid use disorder using a novel approach incorporating mediating variables. Addiction. 2021 08; 116(8):2094-2103. PMID: 33340181.
    Citations:    Fields:    Translation:Humans
  11. Hejazi NS, van der Laan MJ, Janes HE, Gilbert PB, Benkeser DC. Efficient nonparametric inference on the effects of stochastic interventions under two-phase sampling, with applications to vaccine efficacy trials. Biometrics. 2021 12; 77(4):1241-1253. PMID: 32949147.
    Citations: 1     Fields:    Translation:Humans
  12. Boileau P, Hejazi NS, Dudoit S. Exploring high-dimensional biological data with sparse contrastive principal component analysis. Bioinformatics. 2020 06 01; 36(11):3422-3430. PMID: 32176249.
    Citations: 2     Fields:    
  13. Sobh A, Loguinov A, Yazici GN, Zeidan RS, Tagmount A, Hejazi NS, Hubbard AE, Zhang L, Vulpe CD. Functional Profiling Identifies Determinants of Arsenic Trioxide Cellular Toxicity. Toxicol Sci. 2019 05 01; 169(1):108-121. PMID: 30815697.
    Citations: 8     Fields:    Translation:HumansCells
  14. Balighi K, Robati RM, Hejazi N. A dilemma: bullous-pemphigoid-like eruption in scabies or scabies-induced bullous pemphigoid. Dermatol Online J. 2006 May 30; 12(4):13. PMID: 17083868.
    Citations: 4     Fields:    Translation:HumansAnimals
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Funded by the NIH National Center for Advancing Translational Sciences through its Clinical and Translational Science Awards Program, grant number UL1TR002541.