Interpretation of Many-Valuedness in Quality-of-Life Instruments

Abstract

Assessment instruments for functioning in general and quality of life in particular often involve discrete scales with three, four, or five values, or Visual Analogue Scales (VAS) with a range 0–100. VAS scales often need to be downsized and discretized using intervals or clusters. Cutoff points for these intervals/clusters need to be carefully selected and justified. Our objective was to underline the importance of providing clear interpretations of many-valuedness appearing in quality-of-life (QoL) instruments, and to present a methodology for the provision of such clearness. Doing so, we view QoL scales as originating within the World Health Organization (WHO).

Keywords

• assessment instruments
• health
• quality of life
• visual analogue scales