Which outcomes should always be measured in intervention studies for improving work participation for people with a health problem? An international multistakeholder Delphi study to develop a core outcome set for Work participation (COS for Work)

Objective: Synthesising evidence of the effects of interventions to improve work participation among people with health problems is currently difficult due to heterogeneity in outcome measurements. A core outcome set for work participation is needed.

Study design and setting: Following the Core Outcome Measures in Effectiveness Trials methodology, we used a five-step approach to reach international multistakeholder consensus on a core outcome set for work participation. Five subgroups of stakeholders took part in two rounds of discussions and completed two Delphi voting rounds on 26 outcomes. A consensus of =80% determined core outcomes and 50%-80% consensus was required for candidate outcomes.

Results: Fifty-eight stakeholders took part in the Delphi rounds. Core outcomes were: 'any type of employment including self-employment', 'proportion of workers that return to work after being absent because of illness' and 'time to return to work'. Ten candidate outcomes were proposed, among others: 'sustainable employment', 'work productivity' and 'workers' perception of return to work'.

Conclusion: As a minimum, all studies evaluating the impact of interventions on work participation should include one employment outcome and two return to work outcomes if workers are on sick leave prior to the intervention.


Margarita Ravinskaya, Jos H Verbeek, Miranda Langendam, Ira Madan, Suzanne M M Verstappen, Regina Kunz, Carel T J Hulshof, Jan L Hoving; Delphi participants


Journal: BMJ Open
Volume: 13
Issue: 2
Pages: -
Year: 2023
DOI: 10.1136/bmjopen-2022-069174

Further Study Information

Current Stage: Completed
Funding source(s): This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. SV is supported by Versus Arthritis (grant numbers 20385, 20380) and the NIHR Manchester Biomedical Research Centre.

Health Area

Disease Category: Other

Disease Name: N/A

Target Population

Age Range: 18 - 65

Sex: Either

Nature of Intervention: Other

Stakeholders Involved

- Clinical experts
- Consumers (patients)
- Other
- Policy makers
- Researchers

Study Type

- COS (Other)


- Consensus meeting
- Delphi process
- Literature review
- Survey
- Systematic review

The first phase of our project involved an SR on the spectrum of work outcomes used to measure the effect of interventions in published randomised controlled trials (RCTs). In the second phase, we created a framework to aid the selection of work participation outcomes. Phase three involved a survey among reviewers and trial authors showing different reasons and preferences for choosing and using work outcomes. In the fourth phase, we sought international consensus on COS for Work via a Delphi study. In the fifth and final phase, we will make recommendations for clinimetrically sound methods to measure the core outcomes selected during phase 4.