EQ-5D Nomenclature
The following is a clarification of the EQ-5D nomenclature. The purpose is to define standards for the naming of concepts used in describing the EQ-5D and data produced by the EQ-5D. This forms part of a wider task of defining standards for the reporting of the EQ-5D. The advantages of a standard nomenclature are in the comprehension by people of what information about the EQ-5D means. First there should be a clear distinction between the questionnaire designed to measure health status (EQ-5D) and the questionnaire designed to collect valuations for health states defined by the EQ-5D. EQ-5D self-report questionnaire (designed to measure health status).
Term | Description |
EQ-5D | Descriptive system of health-related quality of life states consisting of five dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) each of which can take one of three responses. The responses record three levels of severity (no problems/some or moderate problems/extreme problems) within a particular EQ-5D dimension. |
EQ-5D descriptive system | Standard layout for the above five-dimensional descriptive system, for recording an individual’s current EQ-5D self-reported health state (often referred to as page 2 of the EQ-5D questionnaire) |
EQ-5D self-reported health state | An EQ-5D health state recorded by an individual on the EQ-5D descriptive system. |
EQ VAS | Standard vertical 20 cm visual analogue scale (similar to a thermometer) for recording an individual’s rating for their current health-related quality of life state (often referred to as page 3 of the EQ-5D questionnaire) |
EQ VAS score | Score recorded by an individual for their current health-related quality of life state on the EQ VAS |
EQ SDQ | Standard set of questions concerning socio-demographic variables for use with the EQ-5D valuation questionnaire and a modified version for use with the EQ-5D questionnaire. NB These questions are optional for users. |
EQ-5D self-report questionnaire | Questionnaire, of standard layout, consisting of the EQ-5D descriptive system, the EQ VAS and (if required) the modified version of the EQ SDQ. |
EQ-5D valuation questionnaire (designed to collect valuations for health states defined by the EQ-5D)
Term | Description |
EQ-5D health state | A health-related quality of life state profile described by the EQ-5D. |
EQ-5D VAS | Visual analogue scale, of standard layout, for recording an individual’s ratings of EQ-5D health states. The health states are expressed as a set of five statements, containing one response within each dimension of the EQ-5D. |
EQ-5D VAS score | Score recorded by an individual for an EQ-5D health state on the EQ-5D VAS |
EQ-5D valuation questionnaire | Questionnaire, of standard layout, consisting of the EQ-5D questionnaire (including full EQ SDQ) plus the EQ-5D VAS, and a standard set of instructions. |
EQ-5D index | Index value attached to an EQ-5D state according to a particular set of weights. It may be distinguished by a unique descriptor assigned by the creators of the weights, for example YMA1 EQ-5Dindex might be a value assigned according to the York MVH A1 value set. |