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Joshua Wallach, PhD, MS

Assistant Professor of Epidemiology (Environmental Health)

Research Summary

Dr. Wallach’s research focuses on synthesizing, evaluating, and establishing the best evidence to inform research, regulatory, and public health decisions. His primary area of research, known as meta-research (i.e., the study of research itself), includes the key thematic areas of research methods, reporting/transparency, and research reproducibility. Dr. Wallach’s research interests include meta-analytical methodology, evaluating study biases, clinical trial design/conduct, pharmacoepidemiology, and regulatory science. His work with the Collaboration for Research Integrity and Transparency (CRIT) at Yale focuses on evaluating the tools, standards, and approaches used to assess the safety, efficacy, quality, and performance of FDA-regulated products using epidemiologic and meta-research methods. Dr. Wallach is also a Faculty Affiliate of the Meta-Research Innovation Center at Stanford (METRICS). He is currently working to create a meta-research group with the Department of Environmental Health Sciences, which will focus on environmental exposure/climate change research.


Dr. Wallach teaches EHS 531: Meta-research: Evaluating and Improving Research. Key topics include the philosophy of science; scientific biases and bias assessment; designing and conducting a meta-research project; meta-analytical methodology; database searches; and open-science practices.

Extensive Research Description

Meta-analyses. One component of my research focuses on conducting traditional systematic reviews/meta-analyses and evaluating meta-analytical methodology. For instance, in a recent systematic review and meta-analysis of the effects of rosiglitazone treatment on cardiovascular risk and mortality, we used multiple data sources and varying analytical approaches to: clarify uncertainties about the cardiovascular risk of rosiglitazone; determine whether different analytical approaches are likely to alter the conclusions of adverse event meta-analyses; and inform efforts to promote clinical trial transparency and data sharing []. I also collaborate with students and investigators at Yale and other institutions around the world on meta-analyses of observational and clinical research.

Meta-research. Meta-research is the scientific discipline that focuses on evaluating and improving research practices (i.e. research on research itself). Over the past 4 years, I have led, co-led, or collaborated on a number of projects that have monitored the status and trends in reproducibility and transparency across the biomedical literature. These projects provide key recommendations to improve the scientific process. Furthermore, I have assessed the methodological quality of published randomized controlled trials, including the evidence supporting subgroup analyses.

Pharmaceutical development and real-world evaluation. I also conduct research focusing on evaluating regulatory policies on pharmaceutical development and enhancing the transparency and quality of the research on medical products regulated by the US Food and Drug Administration (FDA). In particular, I have led a number of projects evaluating the quality and quantity of evidence generated before and after drugs receive FDA approval.


Research Interests

Environmental Exposure; Health Policy; Peer Review; Product Surveillance, Postmarketing; United States Food and Drug Administration; Reproducibility of Results; Epidemiologic Research Design; Bias; Conflict of Interest; Drug Approval; Meta-Analysis; Pharmacoepidemiology; Biostatistics; Climate Change

Public Health Interests

Environmental Health; Epidemiology Methods; Health Policy; Substance Use, Addiction; Pharmaceuticals and Medical Devices; Pharmacoepidemiology

Research Image

Selected Publications