806 Abstracts (-10.2 to -47.4) and by worst eye VA (-6.9 to -20.0). An interaction was found on social functioning score: QoL loss was most important when worst eye VA was higher than 1 (-1.1 versus -18.5). Worst eye contributed from 19.9% to 47.4% of the total QoL loss. CONCLU- SION: Worst and best eye VA contributed independently to vision-related QoL. Under isotropic hypothesis, pre- serving VA on the worst eye should contribute to main- tain vision-related QoL on the long term. PMD39 DESCRIPTION OF THE PRINCIPLES OF GOOD PRACTICE FOR TRANSLATION AND CULTURAL ADAPTATION OF PRO MEASURES: ISPOR QOLSIG GROUP Wild DJ 1 , Ford S 2 , Martin M 3 , Eremenco S 4 ,Verjee-lorenz A 1 1 Oxford Outcomes Ltd, Cassington, Oxford, United Kingdom; 2 Pfizer Global Pharmaceuticals, Kalamazoo, MI, USA; 3 Health Research Associates, Inc (HRA), Seattle, WA, USA; 4 Evanston Northwestern Health care, Evanston, IL, USA OBJECTIVES: A series of quality of life special interest groups were set up by ISPOR in 1999. The translation and cultural adaptation group has met six times and has been working towards a set of Principles of Good Prac- tise. METHODS: The translation and cultural adaptation process was divided into requisite components: forward translation and reconciliation, back translation, harmon- isation, and cognitive debriefing and each component was given to a member of the working group. The working group took a consensus of the guidelines and using their knowledge and experience to summarise and suggest the criteria for achieving success. The draft document was then reviewed by all of the members of the QoL special interest groups at ISPOR. RESULTS: Eleven sets of guidelines were identified and critiqued. The document produced by the group is tabular in format and includes four columns: name of step, key components, rationale, and risks of failing to complete the step. CONCLUSION: The document is now being submitted for publication. Further work will continue in order to expand the docu- ment to include discussion of a wide range of PRO’s and cultural adaptation of translations where an existing version exists but which has been developed for use in another culture. PMD40 UTILISATION OF THE FOCUS GROUP TECHNIQUE IN THE DEVELOPMENT OF QUALITY OF LIFE QUESTIONNAIRES Barea N 1 , Gar cia S 1 , Perulero N 1 , Sarmiento M 1 , Badia X 2 1 HOTrials (Health Outcomes Research Europe Group), Barcelona, Spain; 2 Health Outcomes Research Europe Group, Barcelona, Spain The Focus Group(FG)technique is a discussion forum that allows the access to valuable information generated by a group of people under controlled conditions. This is especially useful to explore complex health and psychol- ogy-related topics. Moreover, it has the advantage of being fastest and less expensive than individual interviews and qualitative research techniques. It has also the advan- tage of incorporating the patients’ perspective into the problem analysis and facilitating the interaction to obtain information that would be otherwise inaccessible. In addition, patient’s intervention helps to explore new dimensions of the problem as well as to generate creative ideas giving room for spontaneity and flexibility. Never- theless, and despite of these theoretical advantages the incorporation of the FG technique into the development of QoL questionnaires is apparently somewhat low. OBJECTIVES: To investigate the level of utilisation of the FG technique in the development of health related QoL questionnaires. METHODS: A systematic search of the Medline database from 1993–2003 has been performed. The descriptors used were “quality of life”, “question- naire” and “focus group”. RESULTS: Our search indi- cated that from 67 studies that met our search criteria only 16 used the qualitative technical of FG in the phase of the development of QoL questionnaires. It is impor- tant to point out that 10 out of these 16 publications, in which the FG technique was used, were published during the last 3 years, showing a positive trend. CONCLU- SIONS: Although in the last years there has been a slight increase in the use of FG technique, we consider that it would be necessary to emphasize the importance of this qualitative technique into the development of the QOL questionnaires. This would enhance the active role of patients, taking into account both, incorporation of the patient’s perspective into the analysed problem and iden- tification of other aspects more difficult to approach by the clinician. PMD41 THE NATURE OF THE QUALITY-ADJUSTED LIFE YEAR (QALY) CALCULATION Prieto L 1 , Sacristan JA 2 1 Eli Lilly & Co, Alcobendas, Madrid, Spain; 2 Eli Lilly & Co., Spain, Alcobendas, Madrid, Spain OBJECTIVES: The quality-adjusted life-year (QALY) is a measure of the value of health outcomes. Since health is a function of length of life and quality of life (QoL), the QALY was developed as an attempt to combine the value of these attributes into a single index number. Neverthe- less, QALYs have been criticised on technical and ethical grounds. A salient problem relies on the numerical nature of its constituent parts. The appropriateness of the QALY arithmetical operation is compromised by the essence of the utility scale: while life-years are expressed in a ratio scale with a true zero, the utility is an interval scale where 0 is an arbitrary value for death. In order to be able to obtain coherent results, both scales would have to be expressed in the same units of measurement. The differ-