Elsevier

Social Science & Medicine

Volume 67, Issue 5, September 2008, Pages 874-882
Social Science & Medicine

Valuing the ICECAP capability index for older people

https://doi.org/10.1016/j.socscimed.2008.05.015Get rights and content

Abstract

This paper reports the first application of the capabilities approach to the development and valuation of an instrument for use in the economic evaluation of health and social care interventions. The ICECAP index of capability for older people focuses on quality of life rather than health or other influences on quality of life, and is intended to be used in decision making across health and social care in the UK. The measure draws on previous qualitative work in which five conceptual attributes were developed: attachment, security, role, enjoyment and control. This paper details the innovative use within health economics of further iterative qualitative work in the UK among 19 informants to refine lay terminology for each of the attributes and levels of attributes used in the eventual index. For the first time within quality of life measurement for economic evaluation, a best-worst scaling exercise has been used to estimate general population values (albeit for the population of those aged 65+ years) for the levels of attributes, with values anchored at one for full capability and zero for no capability. Death was assumed to be a state in which there is no capability. The values obtained indicate that attachment is the attribute with greatest impact but all attributes contribute to the total estimation of capability. Values that were estimated are feasible for use in practical applications of the index to measure the impact of health and social care interventions.

Introduction

Current UK policy regarding the provision of both health care and social care for older people suggests that greater integration is required between these two areas (Department of Health, 2001, Glendinning, 2003). Economists' attempts to assist such resource allocation decisions, however, strongly focus on measuring health (in its broadest sense), with proxies for health, life expectancy, and health-related quality of life measures (in particular the Quality-Adjusted Life Year (QALY) (Williams, 1985)) dominating the empirical economic evaluation literature. Many social services interventions, however, may impact more broadly on quality of life (assumed here to encompass the broad range of factors that are important to people in living their lives) rather than health (assumed here to include aspects of physical and mental health). Measures that look only at health in assessing the impact of these interventions would be very likely to underestimate impact.

Given the concern for closer integration, previous work by this research team has concentrated on developing attributes for a new measure of (general) quality of life for older people, rather than health-related quality of life or influences on quality of life (Grewal et al., 2006). The purpose of such a measure would be to provide information for decisions about the allocation of resources across health and social care, rather than just across health. By including dimensions that are concerned with quality of life rather than health alone the measure would enable comparisons across a broader range of interventions. For example, the measure would more easily enable decision makers to compare the value of social service interventions that may improve quality of life without improving health (such as aids and adaptations including, for example, housing interventions; day care; and meals on wheels) with, for example, health interventions that improve both health and quality of life (such as provision of drugs for Alzheimer's or the surgical replacement of hips and knees). This type of measure might also be extremely useful for interventions concerned with the public health of older people, such as mental health services for dementia and depression, measures to reduce falls, continence services, etc. (Department of Health & OPD(PIP), 2004).

Prior work by the research team used in-depth interviews with older people to find out what mattered to them in terms of their quality of life (Grewal et al., 2006). Although discussion initially concentrated upon factors influencing quality of life (activities, relationships, health, wealth, surroundings and religion/faith/spirituality) further probing and analysis suggested that five conceptual attributes were important: attachment (feelings of love, friendship, affection and companionship); role (the idea of having a purpose or “doing something” that is valued, either by the individual and/or by others); enjoyment (notions of pleasure and joy, and a sense of satisfaction); security (feeling safe and secure, not having to worry and not feeling vulnerable); and control (being independent and able to make one's own decisions) (Grewal et al., 2006).

Importantly, the previous study also suggested that informants' quality of life was limited by loss in ability to pursue these attributes (Grewal et al., 2006). So, for example, poor health itself did not reduce quality of life; rather, the important issue was the influence such poor health had upon informants' abilities to achieve these attributes. The work was then linked with the extensive literature on capabilities (Nussbaum, 2003, Robeyns, 2003, Robeyns, 2005) associated particularly with the work of Sen, 1982, Sen, 1992, Sen, 1993, Sen, 2002. Sen distinguishes between functioning and capability as possible foci for evaluation, using the example of the person who is starving due to lack of food compared with the person for whom food is freely available, but who chooses to fast, to indicate why capability instead of functioning might be an important focus of evaluation (Sen, 1993). Here, the five conceptual attributes developed in the previous work are interpreted as a set of functionings, the capability to achieve which appeared to be of importance. The previous work concluded that further development of the measure would focus on developing an index of capability (Grewal et al., 2006). Such an approach has not previously been pursued either within the capabilities or the health economics literature.

It should be stressed that developing a capability index was not the starting point for the original research, but rather one that emerged from careful analysis of the qualitative data. Consequently, whilst an index of capability seems to most closely reflect the values of the older people interviewed and thus draws to a greater extent on the capabilities literature than previous “extra-welfarist” assessments within health economics (Culyer, 1989, Culyer, 1990), the research is consistent with the economic evaluation paradigm in health care research, with the measure intended to provide a useful outcome for economic evaluation. To be useful for this purpose, the measure must be able to be completed by older people participating in studies to determine the impact of interventions and must be linked to a set of values that can provide a weighted measure of outcome. The standard approach within health economics, however, is to use preference elicitation methods that weight (anchor) health against death but here a different approach has been used to anchor the index.

This paper details a number of innovative methods that have been used to develop the measure of capability (the ICECAP1 measure) from the point at which the five conceptual attributes were obtained. In particular, the application of qualitative methods within health economics to develop terminology for the measure, the use of best-worst scaling to develop capability values and anchoring in terms of capability rather than death, represent clear departures from usual practice within the development of measures for use in economic evaluation. The paper thus not only presents results for the final terminology used in the index and the values obtained from a general population sample of older people but also illustrates the successful application of these methods in the context of health economics.

Section snippets

Qualitative work: design

The attributes that emerged from the initial qualitative work were attachment, role, enjoyment, control and security (Grewal et al., 2006). These conceptual terms were clearly not described in ways that would be meaningful to older people who are asked to complete a measure nor to policy makers who have to interpret results. In terms of using an index based on these attributes for policy evaluation in health and social care, those completing the index need to be able to understand the meaning

Qualitative work: design

Table 1 shows the characteristics of informants interviewed during the design stage for the measurement instrument. For reasons of space, it is not feasible to report the development of the terminology for the instrument in detail. Instead, the “security” attribute is used as an exemplar, as this was the most difficult term to clarify. This concept was defined originally by the research team as “ideas of feeling safe and secure, not having to worry and not feeling vulnerable”, influences upon

Discussion

The data and analysis reported in this paper represent an important step towards developing a capability index for older people for use in economic evaluations that cross the health and social care boundary. The index measure includes attributes that are influenced by health, but also by other factors such as bereavement and finances (other negative influences on quality of life noted in the initial conceptual work (Grewal et al., 2006)), as well as non-health interventions such as the

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    This work would not have been possible without the time given up by informants during the qualitative work and the respondents to the surveys. Thanks are also due to Ini Grewal and the survey interviewers. This work was supported by the MRC Health Services Research Collaboration.

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