This module aims to explore the differences in measurement of the widely used EQ-5D instrument using two developed variants. The EQ-5D is a 5-item instrument, designed by a consortium called EuroQol, to measure health-related quality of life. Despite its obvious shortcomings, it is the principal measure recommended by NICE for measuring quality-adjusted life-years (QALYs). QALY measures are a key input into cost-effectiveness evaluations of drug therapies, medical technologies and other healthcare procedures commissioned by NICE for the English NHS. Largely because of the worldwide influence that NICE has, EQ-5D is also an important policy tool in at least nine other countries.
A new version of EQ-5D, designed to improve question wording and increase sensitivity, has been produced and is increasingly being adopted for clinical trials. The original version, with a 3-point response scale, is known as EQ-5D-3L, and the newer version with a 5-point scale is called EQ-5D-5L. The IP carried both versions, with the experiment varying whether the respondent was asked both the 3L and 5L versions or only the 5L version, and the location of these within the questionaire. 1/3 of respondents were asked the 3L version in an early CASI module and 5L in the standard CASI module, 1/3 were asked the 5L in the early CASI module and 3L in the standard CASI module and 1/3 were only asked the 5L version in the standard version.
Random allocation to conditions occurred at the respondent level with an equal (1/3 each) chance. The controlling variable for this experiment is as follows.
eq5dcond on record k_indresp_ip:
1 ASK EQ-5D-3L Late and ASK EQ-5D-5L Early
2 ASK EQ-5D-3L Early and ASK EQ-5D-5L Late
3 ASK EQ-5D-5L Late ONLY
The variables used for this experiment are the following.
On record k_indresp_ip:
eq3lmobear, eq3lcareear, eq3lactear, eq3lpainear, eq3lanxear, eq5lmobear, eq5lcareear, eq5lactear, eq5lpainear, eq5lanxear, eq3lmoblat, eq3lcarelat, eq3lactlat, eq3lpainlat, eq3lanxlat, eq5lmoblat, eq5lcarelat, eq5lactlat, eq5lpainlat, eq5lanxlat
