Modelling valuations for health states: the effect of duration

Title: Modelling valuations for health states: the effect of duration
Author: Dolan, Paul
Publisher: Health policy, 38 (3). pp. 189-203
ISSN: 0168-8510
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Abstract: An important issue which has been raised in the measurement of health status is the effect that the time spent in a health state may have on the way that state is perceived. Recently a set of valuations for health states defined in terms of the EuroQol Descriptive System was generated from a study of over 3000 members of the UK general public. The valuations were elicited using the visual analogue scale (VAS) and time trade-off (TTO) methods and were for states that lasted for 10 years. Using VAS valuations for states lasting 1 month, 1 year and 10 years derived from a subset of respondents to the general population study, this paper presents valuation ‘tariffs’ for all EuroQol states based on the different durations. The results support those of previous studies which suggest that poor states of health become more intolerable the longer they last. Such findings suggest that the results of studies in which the value given to a health state is assumed to be linearly related to the time spent in that health state should be treated with caution and subjected to sensitivity analysis over an appropriate range of values.

The effect of experience of illness on health state valuations

Title: The effect of experience of illness on health state valuations
Author: Dolan, Paul
Publisher: Journal of clinical epidemiology, 49 (5). pp. 551-564
ISSN: 08954356
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Abstract: There is increasing interest in health status measurement and the relative weights that patients and the general public attach to different states of health and illness. One important question that has been raised is whether preferences differ according to the characteristics of the respondents, such as their experience of illness. The results presented in this article suggest that current health status has an important effect on the valuations attached to different health states, with those in poorer health generally giving higher valuations. Past experience of illness, on the other hand, appears to have a negligible effect on valuations. These findings pose real problems for policy makers. To the problem of whose values should count can be added the problem of when these values should count, since the results imply that different valuations may be given by the same respondent depending on how recent their experience of illness was.

Valuing health states: a comparison of methods

Title: Valuing health states: a comparison of methods
Authors: Dolan, Paul and Gudex, Claire and Kind, Paul and Williams, Alan
Publisher: Journal of health economics, 15 (2). pp. 209-231
ISSN: 0167-6296
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Abstract: In eliciting health state valuations, two widely used methods are the standard gamble (SG) and the time trade-off (TTO). Both methods make assumptions about individual preferences that are too restrictive to allow them to act as perfect proxies for utility. Therefore, a choice between them might instead be made on empirical grounds. This paper reports on a study which compared a “props” (using specially-designed boards) and a “no props” (using self-completion booklets) variant of each method. The results suggested that both no props variants might be susceptible to framing effects and that TTO props outperformed SG props.

The time trade-off method: results from a general population study

Title: The time trade-off method: results from a general population study
Authors: Dolan, Paul and Gudex, Claire and Kind, Paul and Williams, Alan
Publisher: Health economics, 5 (2). pp. 141-154
ISSN: 1057-9230
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Abstract: An important consideration when establishing priorities in health care is the likely effects that alternative allocations of resources will have on health-related quality-of-life (HRQoL). This paper reports on a large-scale national study that elicited the relative valuations attached by the general public to different states of health (defined in HRQoL terms). Health state valuations were derived using the time trade-off (TTO) method. The data from 3395 respondents were highly consistent, suggesting that it is feasible to use the TTO method to elicit valuations from the general public. The paper shows that valuations for severe health states appear to be affected by the age and the sex of the respondent; those aged 18-59 have higher valuations than those aged 60 or over and men have higher valuations than women. These results contradict those reported elsewhere and suggest that the small samples used in other studies may be concealing real differences that exist between population sub-groups. This has important implications for public policy decisions.

Inconsistency and health state valuations

Title: Inconsistency and health state valuations
Authors: Dolan, Paul and Kind, Paul
Publisher: Social science & medicine, 42 (4). pp. 609-615
ISSN: 0277-9536
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Abstract: The comparison of scaling methods used to value health states sometimes rests upon an analysis of aggregate scores. This analysis is usually undertaken once “inconsistent’ respondents have been excluded from the data. However, it is important to be able to judge the extent to which respondents as a whole are logically consistent when assigning values to health states. The degree of inconsistency will depend on how the health states are described, how the questionnaire is administered and who the respondents are. This paper analyses the inconsistency rates from two studies in which valuations for EuroQol health states were elicited using the visual analogue scale (VAS) method. The studies differed in design and incorporated several different variants of the standard EuroQol questionnaire, thus providing an opportunity to examine the relative importance of the different factors that were thought to affect inconsistency rates. Our general conclusions are that inconsistency rates are higher for interviewer-based than for postal surveys, possibly due to response bias, and that inconsistency rates are positively related to age and negatively related to educational attainment.

Health state valuations from the general public using the visual analogue scale

Title: Health state valuations from the general public using the visual analogue scale
Authors: Gudex, Claire and Dolan, Paul and Kind, Paul and Williams, Alan
Publisher: Quality of life research, 5 (6). pp. 521-531
ISSN: 0962-934
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Abstract: In the clinical and economic evaluation of health care, the value of benefit gained should be determined from a public perspective. The objective of this study was to establish relative valuations attached to different health states to form the basis for a social tariff for use in quantifying patient benefit from health care. Three thousand three hundred and ninety-five interviews were conducted with a representative sample of the adult British population. Using the EuroQol health state classification and a visual analogue scale (VAS), each respondent valued 15 health states producing, in total, direct valuations for 45 states. Two hundred and twenty-one re-interviews were conducted approximately 10 weeks later. A near complete, and logically consistent, VAS data set was generated with good test-retest reliability (mean ICC=0.78). Both social class and education had a significant effect, where higher median valuations were given by respondents in social classes III–V and by those with intermediate or no educational qualifications. These effects were particularly noticeable for more severe states. The use of such valuations in a social tariff raises important issues regarding the use of the VAS method itself to elicit valuations for hypothetical health states, the production of separate tariffs according to social class and/or education and the appropriate measure of central tendency.