The University of Southampton
University of Southampton Institutional Repository

Identifying and avoiding design related biases in observational studies using the target trial framework

Identifying and avoiding design related biases in observational studies using the target trial framework
Identifying and avoiding design related biases in observational studies using the target trial framework

Observational studies are necessary to provide evidence to inform decision making in the absence of a relevant randomised trial. Although commonly criticised for potential problems due to confounding bias, design related biases in observational studies are often overlooked yet highly prevalent. Design related biases occur because of decisions made by researchers during analyses of observational data. Common design related biases include bias related to selection and treatment misclassification, resulting from misalignment of eligibility ascertainment, treatment strategy assignment, and start of follow-up. Conceptualising the analysis of observational data to estimate the causal effects of interventions as an attempt to explicitly emulate a target trial can help avoid design related biases, so that investigators can instead focus on data related biases (eg, confounding, measurement error) not directly addressed by the framework. Target trial emulation may also help readers appraise an observational study when transparently reported. This article aims to help readers of observational studies identify and avoid design related biases to support the use of observational evidence to inform clinical and policy decision making.

2754-0413
Hansford, Harrison J.
f175946d-61b1-4492-b179-7ba905a30351
Islam, Nazrul
e5345196-7479-438f-b4f6-c372d2135586
Lee, Hopin
21caeab9-6f3d-480e-a639-543c724dae5b
Dickerman, Barbra A.
0f6b20e1-5478-4e23-805e-74c20b74f9dd
Cashin, Aidan G.
e90664b8-66bd-4930-9412-6fd29fa53fef
Hansford, Harrison J.
f175946d-61b1-4492-b179-7ba905a30351
Islam, Nazrul
e5345196-7479-438f-b4f6-c372d2135586
Lee, Hopin
21caeab9-6f3d-480e-a639-543c724dae5b
Dickerman, Barbra A.
0f6b20e1-5478-4e23-805e-74c20b74f9dd
Cashin, Aidan G.
e90664b8-66bd-4930-9412-6fd29fa53fef

Hansford, Harrison J., Islam, Nazrul, Lee, Hopin, Dickerman, Barbra A. and Cashin, Aidan G. (2026) Identifying and avoiding design related biases in observational studies using the target trial framework. BMJ Medicine, 5 (1), [e001280]. (doi:10.1136/bmjmed-2024-001280).

Record type: Article

Abstract

Observational studies are necessary to provide evidence to inform decision making in the absence of a relevant randomised trial. Although commonly criticised for potential problems due to confounding bias, design related biases in observational studies are often overlooked yet highly prevalent. Design related biases occur because of decisions made by researchers during analyses of observational data. Common design related biases include bias related to selection and treatment misclassification, resulting from misalignment of eligibility ascertainment, treatment strategy assignment, and start of follow-up. Conceptualising the analysis of observational data to estimate the causal effects of interventions as an attempt to explicitly emulate a target trial can help avoid design related biases, so that investigators can instead focus on data related biases (eg, confounding, measurement error) not directly addressed by the framework. Target trial emulation may also help readers appraise an observational study when transparently reported. This article aims to help readers of observational studies identify and avoid design related biases to support the use of observational evidence to inform clinical and policy decision making.

Text
BMJMED_TTE_Primer_Revised_5-11-25 - Accepted Manuscript
Available under License Creative Commons Attribution.
Download (1MB)
Text
e001280.full - Version of Record
Available under License Creative Commons Attribution.
Download (945kB)

More information

Accepted/In Press date: 28 January 2026
e-pub ahead of print date: 20 February 2026
Published date: February 2026

Identifiers

Local EPrints ID: 510525
URI: http://eprints.soton.ac.uk/id/eprint/510525
ISSN: 2754-0413
PURE UUID: 261554b1-d36a-4689-8f64-22cbf80f9493
ORCID for Nazrul Islam: ORCID iD orcid.org/0000-0003-3982-4325

Catalogue record

Date deposited: 13 Apr 2026 16:30
Last modified: 14 Apr 2026 02:08

Export record

Altmetrics

Contributors

Author: Harrison J. Hansford
Author: Nazrul Islam ORCID iD
Author: Hopin Lee
Author: Barbra A. Dickerman
Author: Aidan G. Cashin

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×