Abstract
Objectives: The development of measures such as the EQ-HWB (EQ Health and Wellbeing) requires selection of items. This study explored the psychometric performance of candidate items, testing their validity in patients, social carer users, and carers. Methods: Article and online surveys that included candidate items (N = 64) were conducted in Argentina, Australia, China, Germany, United Kingdom, and the United States. Psychometric assessment on missing data, response distributions, and known group differences was undertaken. Dimensionality was explored using exploratory and confirmatory factor analysis. Poorly fitting items were identified using information functions, and the function of each response category was assessed using category characteristic curves from item response theory (IRT) models. Differential item functioning was tested across key subgroups. Results: There were 4879 respondents (Argentina = 508, Australia = 514, China = 497, Germany = 502, United Kingdom = 1955, United States = 903). Where missing data were allowed, it was low (UK article survey 2.3%; US survey 0.6%). Most items had responses distributed across all levels. Most items could discriminate between groups with known health conditions with moderate to large effect sizes. Items were less able to discriminate across carers. Factor analysis found positive and negative measurement factors alongside the constructs of interest. For most of the countries apart from China, the confirmatory factor analysis model had good fit with some minor modifications. IRT indicated that most items had well-functioning response categories but there was some evidence of differential item functioning in many items. Conclusions: Items performed well in classical psychometric testing and IRT. This large 6-country collaboration provided evidence to inform item selection for the EQ-HWB measure.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 525-533 |
| Number of pages | 9 |
| Journal | Value in Health |
| Volume | 25 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2022 |
Funding
Funding/Support: This work was supported by grant 170620 from the UK Medical Research Council and grants 20180460, 20180600, 20190260, 20180450, 20180580 , and 20180520 from the EuroQol Research Foundation . The authors acknowledge the support of the National Institute for Health Research (NIHR) Yorkshire and Humber Applied Research Collaboration (formerly CLAHRC) and the NIHR Clinical Research Network (CRN). The authors acknowledge the invaluable contributions of members of the project steering group, advisory group, and public and patient involvement and engagement groups and Julie Johnson for project administration. We also thank members of staff at the National Institute for Health and Care Excellence who attended project workshops and gave valuable feedback. The authors also thank members of the EuroQol Group Association for their input at plenary and academy meetings and the EuroQol office for their support. The authors also thank the NIHR CRN and the South West Peninsula, Northwest Coast, North Thames, and North East and North Cumbria CRNs, in addition to National Health Service organizations across primary and secondary care for their support with recruitment. Finally, The authors acknowledge the contribution of all the patients, social care users, informal carers, and other members of the public who took part in all the studies across the different countries. Funding/Support: This work was supported by grant 170620 from the UK Medical Research Council and grants 20180460, 20180600, 20190260, 20180450, 20180580, and 20180520 from the EuroQol Research Foundation.The authors acknowledge the support of the National Institute for Health Research (NIHR) Yorkshire and Humber Applied Research Collaboration (formerly CLAHRC) and the NIHR Clinical Research Network (CRN). The authors acknowledge the invaluable contributions of members of the project steering group, advisory group, and public and patient involvement and engagement groups and Julie Johnson for project administration. We also thank members of staff at the National Institute for Health and Care Excellence who attended project workshops and gave valuable feedback. The authors also thank members of the EuroQol Group Association for their input at plenary and academy meetings and the EuroQol office for their support. The authors also thank the NIHR CRN and the South West Peninsula, Northwest Coast, North Thames, and North East and North Cumbria CRNs, in addition to National Health Service organizations across primary and secondary care for their support with recruitment. Finally, The authors acknowledge the contribution of all the patients, social care users, informal carers, and other members of the public who took part in all the studies across the different countries. Conflict of Interest Disclosures: Drs Peasgood, Brazier, Mulhern, Engel, and Yang and Ms Belizan reported receiving grants from the Medical Research Council and the EuroQol Research Foundation during the conduct of this study. Dr Mukuria reported receiving grants from the EuroQol Research Foundation during the conduct of this study and outside the submitted work and reported being a member of the EuroQol Research Association. Dr Brazier, Marten, Kreimeier, Mulhern, Greiner, Engel, and Yang reported being members of the EuroQol Group. Dr Brazier reported being a past member of the EuroQol Group Executive, reported receiving grants and personal fees from the EuroQol Research Foundation outside the submitted work, and reported receiving royalties paid to the University of Sheffield for the use of the SF-6D preference-based measure of health outside the submitted work. Drs Marten, Kreimeier, and Greiner reported receiving grants and nonfinancial support from the EuroQol Research Foundation during the conduct of this study. Dr Luo reported receiving grants and personal fees from EuroQol Research Foundation during the conduct of the study and outside the submitted work. Dr Luo and Mulhern are editors for Value in Health and had no role in the peer-review process of this article. Drs Pickard, Augustovski, and Gibbons and Mses Monteiro and Kuharic reported receiving grants from the EuroQol Research Foundation during the conduct of the study. Ms Kuharic reported receiving a fellowship from Takeda Pharmaceuticals USA outside the submitted work. No other disclosures were reported.
Keywords
- EQ-HWB
- health and wellbeing
- item response theory
- item selection
- measurement development
- psychometrics
- quality-adjusted life-year
ASJC Scopus subject areas
- Health Policy
- Public Health, Environmental and Occupational Health
