People

Principal Investigator and Team

Jukka-Pekka “JP” Onnela
Professor of Biostatistics, Harvard T.H. Chan School of Public Health
Director of the Master of Science in Health Data Science Program
Email: onnela@hsph.harvard.edu
Academic Profile

My research focuses on statistical analysis and mathematical and computational modeling of social and biological networks and their connection to human health. My other main research area is digital phenotyping. Prior to joining the Department of Biostatistics at the Harvard School of Public Health in November 2011, I was a Postdoctoral Research Fellow at Harvard Medical School, a Fulbright Visiting Scholar at the Harvard Kennedy School, and a Junior Research Fellow at the University of Oxford. I received NIH Director’s New Innovator Award in 2013.

Hassan Dawood
Senior Research Operations Manager, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: hdawood@hsph.harvard.edu

I lead the operational execution, product development, contracting, on-boarding, and customer success of the Beiwe research platform and its associated service center. Prior to joining the Onnela Lab, I received my bachelor’s from College of William & Mary in 2010 and worked for Brigham and Women’s Hospital in multiple roles, most recently as the Data & Analytics Manager for the Neurosurgery and Psychiatry departments. I’m passionate about using digital tools in the mental health space and bringing them to underserved populations.

Eli Jones
Software Developer, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: elijones@hsph.harvard.edu

Eli leads the software development for the Beiwe Research Platform. Prior to his time at Harvard, Eli worked for Zagaran as a software developer.

Zhimeng Liu
Research Assistant, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: zhimengliu@hsph.harvard.edu

I am currently pursuing my SM2 in Biostatistics at Harvard T.H. Chan School of Public Health, after graduating with a double major in Biostatistics and Music from the University of North Carolina at Chapel Hill. My research is primarily focused on the advancement of clinical trials and the real-world application of clinical data across a spectrum of health concerns, including cardiovascular and eye diseases as well as mental health. With a growing interest in digital phenotyping’s potential, I aspire to explore its applications in health diagnostics and monitoring. Outside the realm of statistics, music remains my passion and a source of inspiration.

Michelle Dai
Research Assistant, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: michelledai@hsph.harvard.edu

I am a SM Computational Biology graduate student at the Harvard T.H. Chan School of Public Health. My research centers on employing network structures to reveal biological entities with deep learning methods, aiming to decipher the intricate relationships across various health sectors. I am excited in harnessing smartphone-based digital phenotyping, delving deep into behavioral and mental health aspects with the goal of crafting personalized interventions to enhance patient outcomes. I received my bachelor’s degree at Wake Forest University concentrating on Computer Science, Mathematical Statistics, as well as Neuroscience.

Max Melnikas
Research Assistant, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: maxmelnikas@hsph.harvard.edu

I am a student in the Biostatistics SM2 program at the Harvard T.H. Chan School of Public Health. I am interested in the applications of digital phenotyping to health monitoring and diagnostics particularly related to cognitive diseases associated with aging. Before attending Harvard Chan, I graduated from Brandeis University with a Bachelor’s degree in Neuroscience and Biology. In my free time, I love watching basketball and playing games like poker and chess.

Jenny Prince
Research Assistant, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: jprince@hsph.harvard.edu

I am a SM Computational Biology and Quantitative Genetics graduate student at the Harvard T.H. Chan School of Public Health with a prior background in biomedical engineering from Cornell University. My research interests lie in the theoretical underpinnings of both social and multi-omic networks. Intrigued by the intersection of statistics and large-scale biomedical data, I am especially enthusiastic about harnessing the abundant information gleaned from smartphone sensors to gain insights into health outcomes.

Postdoctoral Fellows and Research Associates

Till Hoffman, PhD
Research Associate, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: thoffmann@hsph.harvard.edu

My research connects network models with complex real-world datasets, such as indirect or partial observations of networks. I am particularly interested in open and reproducible science based on data that adheres to the principle of privacy by design—without compromising the insights we can glean. Before joining the Onnela lab, I was a Postdoctoral Research Associate at Imperial College London, Staff Research Scientist at Spotify, and Principal Research Scientist at Sonalytic. I received my Ph.D. from Imperial College London and my master’s from the University of Oxford.

 

Debbie Huang, PhD
Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: debbiehuang@hsph.harvard.edu

My research focuses on developing statistical methods for temporally dense smartphone based data with the goal of better characterizing the behavior of individuals with different mental health conditions. Prior to joining the Onnela lab, I received my MPH and Ph.D. in Epidemiology from Columbia University Mailman School of Public Health.


Marcos Matabuena, PhD
Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: mmatabuena@hsph.harvard.edu

I develop advanced statistical and machine learning methods for digital and precision medicine, primarily focusing on analyzing data from wearable devices in diabetes and physical activity.

As a researcher, I pride myself on my creativity and collaborative nature. I strive to maintain a comprehensive perspective on statistical, mathematical, and biomedical research, recognizing the interconnectedness of these domains. My ultimate goal is to develop robust data analysis tools that will shape the future of medicine. Currently, my research encompasses various areas, including uncertainty quantification, causal inference in digital medicine, and survival analysis models that leverage the power of neural networks. These specific research domains have been motivated by critical biological challenges and the importance of translating these findings into clinical applications in biomedicine.

Patrick Emedom-Nnamdi, PhD
Postdoctoral Research Fellow, Department of Biostatistics, Harvard University
Email: PatrickEmedom@g.harvard.edu

I’m a doctoral student in the Department of Biostatistics with an interest in smartphone-based digital phenotyping and mobile health. Prior to joining the Onnela lab, I received a bachelor’s degree in Mathematical Biology from the University of Pennsylvania. At Penn, I worked under the direction of Dr. Michael Levy in order to construct statistical models aimed at disrupting the spread of vector-borne diseases. My current research within the Onnela Lab focuses on estimating recovery trajectories for surgical patients and assessing optimal recovery strategies.


Yuhua Zhang, PhD
Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: yuhuazhang@hsph.harvard.edu

My research focuses on statistical modeling of large-scale network data. In particular, the community detection and link prediction problems. I’m broadly interested in statistical machine learning and challenges in network science. Before joining the Onnela lab, I received my PhD degree in Biostatistics from the University of Michigan.

Graduate Students

Emma Crenshaw
Doctoral Student, Department of Biostatistics, Harvard University
Email: emma_crenshaw@g.harvard.edu

I’m a doctoral student in the Department of Biostatistics interested in network science, particularly. Prior to joining the department, I worked for two years as a statistician at RTI providing statistical support for clinical and observational studies that investigated topics ranging from maternal and child health to opioid use disorder. I received my bachelor’s degree in Biostatistics from the University of North Carolina at Chapel Hill. My current research within the Onnela Lab focuses on simulating infectious disease epidemics using mechanistic network models.

Josh Barback
Doctoral Student, Department of Biostatistics, Harvard University
Email: barback@fas.harvard.edu

Max Wang
Doctoral Student, Department of Biostatistics, Harvard University
Email: maxwang@g.harvard.edu

I’m a doctoral student in the Department of Biostatistics. My research focuses on the applications of network science to infectious diseases, and I’m particularly interested in the ways knowledge about contact networks can affect statistical inferences on epidemic dynamics. Before joining the Onnela Lab, I received my bachelor’s degree in Electrical Engineering from the University of California, Los Angeles.

Lab Affiliates

Heather Mattie, P.h.D.
Instructor, Department of Biostatistics, Harvard University
Email: hemattie@hsph.harvard.edu

Heather Mattie is Instructor of Data Science and the executive director of the Health Data Science Masters program at the Harvard T.H. Chan School of Public Health. She completed her doctorate degree in Biostatistics at Harvard University, and master’s and bachelor’s degrees in Mathematics from Claremont Graduate University and the University of La Verne. Her research interests include tie strength estimation and prediction, network data imputation, and estimating the impact of local neighborhoods on the spread of disease.

Joel Salinas, M.D., M.B.A.
Behavioral Neurology and Neuropsychiatry Fellow, Departments of Neurology and Psychiatry, Massachusetts General Hospital, Harvard Medical School

I am a neurologist with clinical expertise in behavioral neurology and neuropsychiatry and research training in epidemiology and social determinants of neurologic disease outcomes.  My long-term goal is to develop and deploy strategies to prevent the development of devastating chronic brain disease.  My work in the lab focuses on investigating predictors and modifiable risk factors of age-related neurologic disease and its sequelae using social networks from large epidemiologic cohorts.  After graduating from Cornell University, I completed medical school at the University of Miami Miller School of Medicine followed by a neurology residency at the Massachusetts General Hospital and the Brigham and Women’s Hospital and completing a fellowship in Behavioral Neurology and Neuropsychiatry at Massachusetts General Hospital.

Linda Valeri, P.hD.
Assistant Professor of Biostatistics, Columbia University Mailman School of Public Health
Adjust Assistant Professor of Epidemiology, Harvard T.H. Chan School of Public Health
My research centers on causal inference with a focus on statistical methods to investigate mediating mechanisms and causal interaction in longitudinal data arising from mobile health studies. Furthermore, I develop statistical approaches for measurement error correction, missing data imputation and more generally for bias analyses in observational studies.

Kori Zachrison, MD, MSc
Assistant Professor of Emergency Medicine at Massachusetts General Hospital and Harvard Medical School
Email: kzachrison@partners.org

I am Assistant Professor of Emergency Medicine at Massachusetts General Hospital and Harvard Medical School. In addition to my clinical practice, I am a health services researcher currently funded by a K08 from the Agency for Healthcare Research and Quality. My work focuses on stroke systems of care, including applications of network science to stroke systems, and is mentored by Dr. Onnela.

Alumni

Georgios Efstathiadis
Research Assistant, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: gefstathiadis@hsph.harvard.edu

I am a SM Health Data Science graduate student at the Harvard T.H. Chan School of Public Health. I provide support with data collection and processing to teams using the Beiwe research platform and I am also maintaining and updating the Forest library for analyzing digital phenotyping data created by the lab. My research interests lie in applications of Machine Learning methods using digital phenotyping data for gaining insights into the health outcomes of people at risk. My background is in Bayesian Statistics, and I completed my bachelor’s degree in Mathematics with Statistics at the University of Bristol, Bristol, UK.

Joanna Kennedy
Research Assistant, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: joannakennedy@hsph.harvard.edu

I am a SM Health Data Science graduate student at the Harvard T.H. Chan School of Public Health. I am excited by the potential for digital phenotyping to compliment current methods of differentiating, diagnosing, and treating mental health conditions. I am passionate about creating accessible and effective healthcare to help disadvantaged groups, particularly those struggling with mental health. Before starting at Harvard, I graduated from MIT in 2022 with a Bachelor’s degree in Computer Science, and Brain and Cognitive Sciences.

Hali Hambridge
Doctoral Student, Department of Biostatistics, Harvard University
Email: hhambridge@g.harvard.edu

I’m a doctoral student in the Department of Biostatistics interested in network science. Prior to joining the department, I worked for several years as a statistical analyst, exploring novel ways to effectively deliver care to high-risk patients, to appropriately measure hospital performance, and to administer free and reduced-price meals to school students. I also completed fellowships at the National Institutes of Health and the Food and Drug Administration. I obtained my bachelor’s degree in biometry and statistics from Cornell University, as well as master’s degrees in epidemiology and biostatistics from Johns Hopkins University.

Octavious Smiley
Doctoral Student, Department of Biostatistics, Harvard University
Email: Octavioustalbot@g.harvard.edu

I’m a doctoral student in the Department of Biostatistics interested in network science. Prior to joining the department, I attended Morehouse College as a Math Major. I also took a brief break, after passing my qualifying exams, to develop my interest in network science while working at Northwestern University. My current research, within the Onnela Lab, focuses on graphical tools to improve the visual utility of networks, and utilizing Approximate Bayesian Computation to recover the stochastic processes in network formation.


Marcin Straczkiewicz, PhD
Research Associate, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: mstraczkiewicz@hsph.harvard.edu

I received my master’s degree in Digital Signal and Image Processing from Cranfield University, U.K. and a doctoral degree in Automatics and Robotics from AGH University of Science and Technology in Krakow, Poland. My research is focused on developing novel statistical methods for the quantification of human movements using wearable devices, primarily accelerometers and smartphones.

Thien Le, PhD
Research Associate, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: thle@hsph.harvard.edu

My research interest focuses on network structures and their connection with different interaction systems such as the disease spreading system or the nervous system. Before joining the Onnela Lab, I completed my Ph.D. in Statistics in May 2020 at Michigan State University under the direction of Dr. Ping-Shou Zhong. My Ph.D. dissertation developed new methodologies in estimating and testing network structures for high-dimensional data. At Michigan State University, I also worked in a variety of projects in different disciplines such as biology, healthcare, or agriculture under the roles of a statistical consultant and a research assistant. At the Onnela lab, I focus on developing methods in the intersection of Approximate Bayesian Computation and Statistical Network Science. In my free time, I enjoy swimming, practicing martial arts, and meditating.

Julia Olsen
Research Assistant, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: jolsen@hsph.harvard.edu

I am an SM candidate in Epidemiology at the Harvard T.H. Chan School of Public Health. I provide support with data collection and processing through the Beiwe research platform. I am excited by the potential of digital phenotyping to further the understanding of human health, especially psychiatric and neurologic conditions for which accurate self-reporting may not be feasible. Prior to coming to Harvard, I obtained my Bachelor’s degree in Neuroscience at Vanderbilt University and worked in healthcare strategy consulting for two and a half years.

Marta Karas, PhD
Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: mkaras@hsph.harvard.edu

At the Onnela lab, my research is focused on developing new statistical and machine learning methods in smartphone-based digital phenotyping. Formerly, I worked on methods for processing, features extraction and analysis of accelerometry data, methods for power estimation in complex settings, and graph-informed regularization methods for regression. I received my master’s degree in Mathematics (Mathematical Statistics) from Wroclaw University of Science and Technology in Wroclaw, Poland, and a doctoral degree in Biostatistics from Johns Hopkins University in Baltimore, MD, USA.

Zach Clement
Research Assistant, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: zclement@hsph.harvard.edu

I’m currently a SM Biostatistics student at the Harvard T.H. Chan School of Public Health. I provide support with data processing and data collection in the Beiwe Service Center. I’m fascinated by the potential that digital phenotyping has to help us measure and improve patient health, and I enjoy solving problems that arise when trying to derive meaning from these types of data. I completed my Bachelor’s degree in Psychology and Statistics at Brigham Young University in Provo, Utah, USA.

Kenzie W. Carlson
Senior Manager, Department of Biostatistics, Harvard T.H.Chan School of Public Health
Email: kcarlson@hsph.harvard.edu

Prior to joining the Onnela Lab, I received my bachelor’s from Indiana University in 2013 and worked for Accenture for three and a half years. I am especially interested in improving health outcomes through technology and data. I completed my MPH in Health Management at the Harvard T.H. Chan School of Public Health in 2022 and have joined the Digital Strategy team at Takeda Pharmaceuticals.

Louis Raynal
Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: llcraynal@hsph.harvard.edu

Before joining the Onnela Lab, I received a master’s and a doctorate degree in biostatistics from the University of Montpellier, France. My current research is in statistical network science, more precisely I am focusing on the use and development of Approximate Bayesian Computation methods for the analysis of mechanistic network models.

Jonathan Larson
Graduated Doctoral Student, Department of Biostatistics, Harvard University

Greyson Liu
Graduated Doctoral Student, Department of Biostatistics, Harvard University

Anna Beukenhorst
Former Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health

Shahab Haghayegh
Former Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health

Aarti Sathyanarayana
Former Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health

John T

John Torous, M.D.
Resident Physician in the Department of Psychiatry, Brigham and Women’s and Beth Israel Deaconess Medical Center, Harvard Medical School
Email: jtorous@bidmc.harvard.edu

Ian Barnett
Assistant Professor, Department Biostatistics and Epidemiology, University of Pennsylvania, School of Medicine
Email: ibarnett@mail.med.upenn.edu

Sixing Chen
Former Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: sixingchen@hsph.harvard.edu

Clare

Clare Rosenfeld Evans
Faculty Fellow, Department of Sociology, University of Oregon
Email: cevans@uoregon.educevans@mail.harvard.edu

Seth

Seth Greenwood
Former Master’s Student, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: sdg163@mail.harvard.edu

Guy

Guy Harling (joined with Till Bärnighausen)
Former Postdoctoral Research Fellow, Department of Global Health and Population, Harvard T.H. Chan School of Public Health
Email: gharling@hsph.harvard.edu

Emily Huang
Assistant Professor, Wake Forest University
Email: huange@wfu.edu

Felipe Montes pic

Felipe Montes Jiménez
Ceiba Complex Systems Research Center (Colombia)
Email: felipemontesj@gmail.com

xiaoyuliXiaoyu Li
PhD in Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health
Email: xil288@mail.harvard.edu

Jeffrey Lienert
NIH OxCam Scholars Program (D.Phil in Network Science at Oxford University)
Email: jpl091@mail.harvard.edu

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Jeanette Lorme
MD Candidate at Rush Medical College
Email: jeanette.lorme@gmail.com

Reiko

 Reiko Nishihara
Postdoctoral Research Fellow at Dana-Farber Cancer Institute, Harvard Medical School, and Harvard T.H. Chan School of Public Health
Email: rnishiha@hsph.harvard.edu

Juan Fernández-Gracia (joined with Caroline Buckee)
Former Postdoctoral Research Fellow, Department of Biostatistics and Department of Epidemiology, Harvard T.H. Chan School of Public Health
Email: juanfernandez1984@gmail.com

Alison Hwong
MD-PhD Candidate, Harvard Medical School and Graduate School of Arts of Sciences, PhD Program in Health Policy
Email:alison_hwong@hms.harvard.edu

David Kim

David Kim
MD/PhD Candidate, Harvard Medical School and Graduate School of Arts and Sciences
Email: david_kim@hms.harvard.edu

Matt

Mathew Kiang
Ph.D. in Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health
Email: mkiang@mail.harvard.edu

Fei Li
Ph.D., Department of Biostatistics, Harvard University
Email: fli@fas.harvard.edu

Eric

Eric J. Ma
Runstadler Lab, Biological Engineering, MIT
Email: ericmjl@mit.edu

Flora 2

Flora Or
Ph.D., Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health
Email: jfo256@mail.harvard.edu

Patrick Staples
Ph.D. and Postdoctoral Research Fellow, Department of Biostatistics, Harvard T.H. Chan School of Public Health
Email: ctphoenix@gmail.com