Assessing content validity: challenges of conducting systematic reviews of patient-reported outcome measures and recommendations to improve the application of COSMIN guidance

Purpose
Systematic reviews of Patient-Reported Outcome Measures (PROMs) are essential for selecting appropriate measures for research and clinical practice. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines provide a standardised framework for evaluating measurement properties of PROMs, with content validity considered to be the most important property, yet the most complex and poorly reported. This study aimed to report common challenges researchers face when evaluating content validity in systematic reviews on the quality of PROMs, and to provide clear, experience-informed recommendations to overcome them.

Method
A narrative synthesis of challenges in evaluating content validity in systematic reviews of PROMs is presented. Challenges were extracted from Elsman et al.’s umbrella review and from stakeholder consultations with the authors of this manuscript, providing practical recommendations and illustrative examples.

Results
Seven challenges were identified: (1) feasibility of conducting a systematic review on the quality of PROMs, (2) identifying all articles describing PROM development for the target population, (3) managing different versions of PROMs, (4) poor reporting in primary studies (5) ambiguity in classifying studies as PROM development or content validity studies, (6) applying the criteria for content validity, specifically, to the results of development studies, and (7) accurately framing the scope of the PROM and the review. Recommendations include narrowing the scope of the review, conducting supplementary searches, treating PROM versions distinctly, and guidance on how to interpret poorly reported studies.

Conclusion
These insights support consistent application of COSMIN guidelines and improve PROM selection and use, complementing existing COSMIN materials.

Contributors

Rachel L. Chambers, Silvia Lahuerta-Martín, Ana M. Greco, Rachael Pattinson, Timothy Pickles, Jason Hassan & Lidwine B. Mokkink

Publication

Journal: Quality of Life Research
Volume: 35
Issue: 157
Pages: -
Year: 2026
DOI: https://doi.org/10.1007/s11136-026-04261-5

Further Study Information

Current Stage: Completed
Date:
Funding source(s): Rachel L Chambers is funded by the BuildPall capacity building programme at the Cicely Saunders Institute, funded by Cicely Saunders International (charity reg. 1087195).


Health Area

Disease Category:

Disease Name:

Target Population

Age Range: Unknown

Sex:

Nature of Intervention:

Stakeholders Involved

- Clinical experts
- Researchers

Study Type

- COS methods research

Method(s)

- Consultations
- Literature review

Identified challenges reported in systematic reviews of PROMs by drawing on a published umbrella review. In 2024, Elsman et al. [8] conducted an umbrella review of the methodological quality of 100 systematic reviews of health-related outcome measurement instruments, randomly selected from the COSMIN database of systematic reviews (https://www.cosmin.nl/tools/database-systematic-reviews/). From this umbrella review, we selected reviews that reported on content validity. Each article was reviewed by a member of the review team (RLC, LBM, RP, or SLM), and data were extracted on (1) challenges or difficulties in reviewing or rating content validity in primary studies and (2) author-reported solutions. Systematic reviews were not identified through any other searches.