- EQ-5D is a standardized instrument for use as a generic measure of the quality of health-related life and of health outcome (for example in cost-effectiveness analyses). It is particularly associated with the QALY (quality-adjusted life-year). It is designed for self-completion by respondents and is suited for use in postal surveys, clinics and face-to-face interviews. It is cognitively simple, taking only a few minutes to complete. Instructions to respondents are included in the questionnaire. The EQ-5D has five dimensions: Mobility, Self-care, Usual activity, Pain/discomfort, Anxiety/Depression. The traditional EQ-5D instrument described each dimension in terms of three levels: 1- no problem, 2 - some problem, 3 - extreme problem. More recently, the EuroQol Group has developed a five-level version (EQ-5D-5L) and an instrument validated for self-completion by children and young people (EQ-5D-Y). In each case, the instrument comprises two parts: respondents rate their health on the dimensions/levels and record an overall assessment of their health on a visual analogue scale, the EQ-VAS.