Task Force on the Development of a Common Instrument to Measure Health States: Identification of Domains

1. Working Paper No.2 22 November 2005 STATISTICAL COMMISSION and STATISTICAL OFFICE OF THE UN ECONOMIC COMMISSION FOR EUROPEAN COMMUNITIES EUROPE (EUROSTAT) CONFERENCE OF EUROPEAN WORLD HEALTH STATISTICIANS ORGANIZATION (WHO) Joint UNECE/WHO/Eurostat Meeting on the Measurement of Health Status (Budapest, Hungary, 14-16 November 2005) Session 2-Invited paper Task Force on the Development of a Common Instrument to Measure Health States:Identification of Domains Sarah Connor Gorber; Cameron N. McIntosh; Julie Bernier; Jean-Marie Berthelot; Michael C. Wolfson Statistics Canada Ottawa, Ontario, Canada

2. Identifying Domains for the Common Instrument • Objective Identify a compact yet comprehensive set of domains that cover the major aspects of health (i.e., physical, mental, and social); and are meaningful in an international context. • Method Appliedpre-established criteria to reduce an initially extensive list of candidate domains into a more manageable subset of core domains; periodic open discussions among task force members supplemented the criteria

3. Initial List of Candidate Health Domains

4. Initial List of Candidate Health Domains

5. Criteria for Domain Selection: Global and Relational (1) Global Criteria – do not depend on other domains in the list (a) Face validity (b) Within, on, or near the skin (c) Importance for population health monitoring (d) Feasibility (potential for assessment with a variety of methods) (e) Consistency across varying socio-cultural contexts (f) Heterogeneity (sufficient inter-individual variability in functioning) (g) Can be described in terms of a clear series of functional levels (h) Reflect key selected ideas of the ICF

6. Criteria for Domain Selection: Global and Relational (2) Relational Criteria – depend on other domains in the list (a) Breadth of coverage (b) Statistical independence (c) Structural independence (d) Parsimony (comprehensive yet compact set of domains) (e) Amenability to preference measurement

7. Selection of Domains • Initial list of candidate domains was minimized via an iterative process: assessment against the established criteria plus discussion and debate among task force members Examples Mobility and Dexterity – included since they are fundamental and largely independent health domains covering much of the spectrum of day-to- day physical functioning; measured in the bulk of national survey modules and standardized measuring instruments Self-care and Usual Activities – excluded given considerable redundancy with Mobility and Dexterity; might also be difficult to operationally define a vague concept like “usual activities”, such that it has consistent meaning and interpretation across varying socio-cultural contexts

8. Controversies • Deciding on the status of certain domains posed much more difficulty than others, and inspired lively discussions among task force members Examples Social Relationships – disagreement as to whether this domain could be conceptualized as “within-the-skin.” However, we could lose information by excluding the social aspect of health, so it was agreed to try and assess Social Relationships in terms of capacity Speech – disagreement as to whether there was sufficient heterogeneity in functioning on this domain to warrant its direct Inclusion on the common instrument. It was decided that Speech would not be directly assessed but rather captured by Social Relationships (which would include aspects of Communication)

9. Selected Domains Assessing the 30 candidate domains, using the pre-established criteria as well as refinements based on discussion sessions, resulted in the selection of the following 10 domains for inclusion on the common instrument: