SF-6D - Calculating QALYs from the SF-36 and SF-12

The SF-6D provides a means for using the SF-36 and SF-12 in economic evaluation by estimating a preference-based single index measure for health from these data using general population values. The SF-6D allows the analyst to obtain quality adjusted life years (QALYs) from the SF-36 for use in cost utility analysis.
Technology No.

SF-6D: A brief overview

The SF-36 has become the most widely used measure of general health in clinical studies throughout the world. It currently generates eight dimension scores and two summary scores for physical and mental health. Whilst such scores provide an excellent means for judging the effectiveness of health care interventions, they have only a limited application in economic evaluation because they are not based on preferences.

The SF-6D provides a means for using the SF-36 and SF-12 in economic evaluation by estimating a preference-based single index measure for health from these data using general population values. The SF-6D allows the analyst to obtain quality adjusted life years (QALYs) from the SF-36 for use in cost utility analysis.

If the results of your Project are published, the user shall, if appropriate, cite the publications listed in the References section tab. 

FAQ

 What is available from this website?

Programmes that convert your SF-36 or SF-12 data into an SF-6D health state and corresponding utility score for each observation in your dataset.

What do the programmes do? 

The programme will generate for each row of your dataset the six dimension scores of the SF-6D, the six digit health state and a utility value anchored at 1 for full health and 0 for dead.

What is the SF-6D? 

The SF-6D is a generic preference-based single index measure of health that can be used to generate QALYs and hence which can be used in cost-utility analysis.

What types of programmes are available? 

There are excel, SPSS and SAS programmes available to convert SF-36 data into SF-6D data and there are SPSS and SAS programmes available to convert SF-12 data into SF-6D.

All programmes generate the SF-6D utility score estimated using a set of parametric preference weights obtained from a sample of the general population using the recognised valuation technique of standard gamble. In addition a new excel programme is now available from the University of Sheffield to convert SF-36 data into the SF-6D utility score estimated using a set of non-parametric Bayesian preference weights. These nonparametric preference weights are an improvement on the parametric preference weights as the nonparametric model has many advantages over the conventional parametric random effects model which is reflected in improvements in the predictive ability of the model. For further details see Kharroubi et al. (2007). 

Furthermore a new excel programme is available to convert SF-36 data into the SF-6D utility score estimated using a set of preference weights obtained using an ordinal valuation technique for a sample of the general population. The estimates using ordinal data represent an alternative value set based on a different valuation technique which produces estimates that are comparable to estimates produced using standard gamble data. For further details see McCabe et al. (2006). 

Can I use the SF-6D algorithm for a different study other than the study described in the initial application? 

No. You need a licence agreement for each study for which you use the SF-6D algorithm.

How does the SF-6D generate preference scores? 

The SF-6D comes with a set of preference weights obtained from a sample of the general population in the UK using the recognised valuation technique of standard gamble. Members of the general population in the UK were asked to value a selection of health states from which a model has been estimated to predict all the health states described by the SF-6D.

Is there a written document outlining the process for converting the SF-36 data to SF-6D scores? 

Instructions are available for each of the programmes available but these do not outline how the process can be done using a different software package. We currently have algorithms available for use on SF-36 data in SAS, SPSS and excel, and for SF-12 data in SAS and SPSS.

Can I use these programmes for a study outside the UK? 

The SF-6D utility score is generated using preference weights obtained from a sample of the general population in the UK. The UK population may have different preferences to non-UK populations.

Video 

Please watch this video for more information

Valuation Surveys in Other Countries 

There is emerging evidence that SG health state values differ between countries for SG. There have been valuation surveys completed in Japan, Hong Kong, Portugal, Brazil and Spain using similar methods to those used

in UK. Details on these surveys can be found in the publications listed at the bottom of this note. Surveys have also been undertaken in Australia and Singapore, but the results have yet to be published.

Researchers interested in using the SF-6D in these countries should contact the names listed below:- 

Australia

Rosalie Viney: rosalie.viney@chere.uts.edu.au

Brendan Mulhern: Brendan.Mulhern@chere.uts.edu.au

Brazil

Luciane Cruz:lncruz@ig.com.br

Marcelo Fleck: mfleck.voy@zaz.com.br

Hong Kong

Cindy Lam: clklam@hku.hk

Sarah McGhee: smmcghee@hkucc.hku.hk

Japan

Shunichi Fukuhara: fukuhara@pbh.med.kyoto-u.ac.jp

Portugal

Lara Nobre Noronha Ferreira: lnferrei@ualg.pt

Pedro Lopes Ferreira: pedrof@fe.uc.pt

Singapore

Nan Luo: medln@nus.edu.sg

Spain

José María Abellán: dionisos@um.es

Publications on valuation surveys conducted in other countries:

Lam CLK, Brazier J, McGhee SM. Valuation of the SF-6D health states is feasible, acceptable, reliable and valid in a Chinese population. Value in Health 2008;11:295-303.

Brazier JE, Fukuhara S, Roberts J, Kharoubi S et al. Estimating a preference-based index from the Japanese SF-36.

Journal of Clinical Epidemiology; 62(12): 1323-1331.

Ferreira LN, Ferreira PL, Brazier J, Rowen D. A Portugese value set for the SF-6D. Value in Health 2010; 13(5): 624-630.

Abellan-Perpiñan JM, Sanchez-Martinez FI, Martinez-Perez JE, Mendez I. Lowering the 'floor' of the SF-6D scoring algorithm using a lottery equivalent method. Health Economics 2012: 21; 1271-1285.

Méndez I, Abellán JM, Sanchez FI, Martinez JE. Inverse probability weighted estimation of social tariffs: An illustration using SF-6D value sets. Journal of Health Economics 2011: 30; 1280-1292.


Placing an order

We ask the following information to be provided at 'checkout' for both commercial and non-commercial orders:

What is the title of study in which SF-6D will be used?

What is the duration (term) of the study?

How large is the trial (number of individuals)?

What is the age range of the study participants?

What is the intended clinical / disease area?

What is the purpose for using SF-6D in this study?

Duration

Please note that the Duration of the licence is the duration of the study specified at checkout.

SF6D Commercial Use Licence
Licence for commercial organisations - please contact us for price

Term: perpetual

Price: TBD

Non Commercial - Sft - FOC licence - SF-6D
Licence for academic/non-commercial institutions

Term: perpetual

Price: £0.00 excl. VAT