Valuing health using visual analogue scales and rank data: does the visual analogue scale contain cardinal information?
AbstractValuation studies have favoured standard gamble (SG) and time trade off techniques (TTO) over visual analogue scales (VAS). The lack of observable trade off properties of VAS precludes preferences being measured on a cardinal scale. The inferences, and indeed the premise, of many perceived VAS deficiencies have been debated and, as part of this on-going debate, Brazier and McCabe (2007) asked whether VAS data added anything to rank data; echoing the suggestion that VAS functioned primarily as a prop for ranking exercises (Torrance et al 2001). Previous studies suggest that analyses of ordinal (rank data) can provide valuation functions broadly equivalent to cardinal health state data models (Salomon, 2003; McCabe et al, 2006). This paper adds to the debate by considering whether ordinal preferences, cardinal differences, and cardinal scores from VAS data provide substantively different valuation algorithms. That is, is potentially valuable information lost by using ordinal (rank) data rather than cardinal VAS scores? In the case where a cardinal difference model can provide a substantively better fit than an ordinal preference model, then we can say that the VAS contains useful cardinal information that cannot be incorporated into an ordinal model. A further aim is to assess whether VAS-based ordinal preferences (rather than TTO- or SG-based ordinal preferences) are likely to be sufficient reliably to inform policy. Using rescaled data from a UK general population survey seven separate random effects logit regressions were carried out for ordinal preferences and seven for cardinal differences. In contrast to previous studies the analyses found that ordinal preference models appear to give different results to cardinal data. Ordinal preference data performed worse than the cardinal difference suggesting that: (1) VAS contains at least some relevant and useful cardinal data and (2) ignoring such data worsens performance of the resulting measures.
Download InfoIf you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.
Bibliographic InfoPaper provided by Academic Unit of Health Economics, Leeds Institute of Health Sciences, University of Leeds in its series Working Papers with number 0901.
Length: 17 pages
Date of creation: 2009
Date of revision:
Contact details of provider:
Phone: Charles Thackrah Building, 101 Clarendon Road, LEEDS LS9 2LJ
Fax: +44 (0) 113 343 3470
Web page: http://medhealth.leeds.ac.uk/auhe
More information through EDIRC
Visual analogue scales; rating scale; ordinal preferences; health state valuation; preference-based health measures;
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- McCabe, Christopher & Brazier, John & Gilks, Peter & Tsuchiya, Aki & Roberts, Jennifer & O'Hagan, Anthony & Stevens, Katherine, 2006. "Using rank data to estimate health state utility models," Journal of Health Economics, Elsevier, vol. 25(3), pages 418-431, May.
- John Brazier & Christopher McCabe, 2007. "Is there a case for using visual analogue scale valuations in CUA' by Parkin and Devlin a response: 'yes there is a case, but what does it add to ordinal data?," Health Economics, John Wiley & Sons, Ltd., vol. 16(6), pages 645-647.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Thomas Veale).
If references are entirely missing, you can add them using this form.