Box 2.

Guidance on EQ-VAS data provided by the EuroQol Group

The respondent rates his/her health state by drawing a line from the box marked “Your health state today” to the appropriate point on the EQ VAS

Sometimes, respondents tend to rate their health state by placing a mark on the scale instead of drawing a line. There is no reason why this could not be interpreted as a valid response

If the line does not cross the scale, the value horizontally opposite where the line stops should be taken and not where it would be if hypothetically extended. It is important to ensure that the respondent is not prompted in any way by the administrator and that it is the respondent’s own rating of health-related quality of life that is being recorded

In order to achieve comparable results, it is necessary to adhere to the standard text and instructions and layout of EQ-5D. This is especially relevant for EQ VAS as this is a graphical representation of the value of health (it is important for example that the scale should be a standard 20 cms)

A three-digit number between 000 and 100 is read off the scale, from the exact point where the line crosses the scale, for example, 046 or 069. For comparative purposes, we recommend that: missing response is coded as “999”; ambiguous response is coded as “888” Source: [4]