Exploring the origin and conceptual framework of the EQ VAS.

PURPOSE

The objective of this paper is to report on the origin of the EQ VAS and current understanding of the EQ VAS conceptual framework via a literature search based on the snowball approach.

METHODS

A review was conducted in two steps: (1) a citation search and (2) a search of the EuroQol group's grey literature.

RESULTS

The findings indicate that the EQ VAS was originally designed as a warm-up task for valuing hypothetical health states. The characters of the EQ VAS reflect its valuation origin, such as drawing a line (the previous version), vertical orientation, and choice of end labels. None of these design elements of the EQ VAS were chosen for the purpose of measuring self-reported overall health. Despite this, the EQ VAS proves to be a valid self-reported health status measure with its psychometric properties demonstrated in various general and clinical populations. We found a dearth of literature addressing the conceptual framework of EQ VAS as a measure of self-rated overall health.

CONCLUSION

With its potential as a powerful measure of overall health, further research into EQ VAS design, conceptual framework and empirical function is warranted.