A critical look at observational studies

Torgutalp M, Sahin D, Tascilar K (2026)

Publication Type: Journal article, Review article

Publication year: 2026

Journal

Current Opinion in Immunology Elsevier

Book Volume: 100

Article Number: 102778

DOI: 10.1016/j.coi.2026.102778

Abstract

Observational studies serve as a critical alternative when randomized trials are precluded by ethical concerns, high costs, or the need for rapid evidence-based hypothesis generation. Increasing reliance on routinely collected observational data (electronic health records, registries, and claims) has been accompanied by an increase in the risk of systematic errors that might threaten the validity. In this review, we focus on a selected set of common and crucial issues, confounding, and the use of directed acyclic graphs to describe and analyze causal relationships. We also highlight selection processes that can induce collider bias and create spurious associations between exposure and outcome. Time-varying confounding, where prior treatment affects future confounders, necessitates the use of specific estimation methods. We discuss measurement error and misclassification in routinely collected data and time-to-event pitfalls, the handling of competing events, and missing data.

Authors with CRIS profile

Koray Tascilar Department of Medicine 3 – Rheumatology and Immunology

Involved external institutions

Humboldt-Universität zu Berlin DE Germany (DE) Charité - Universitätsmedizin Berlin DE Germany (DE)

How to cite

APA:

Torgutalp, M., Sahin, D., & Tascilar, K. (2026). A critical look at observational studies. Current Opinion in Immunology, 100. https://doi.org/10.1016/j.coi.2026.102778

MLA:

Torgutalp, Murat, Didem Sahin, and Koray Tascilar. "A critical look at observational studies." Current Opinion in Immunology 100 (2026).

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