Table 1 COSMIN taxonomy of measurement properties [29]
Domain | Measurement properties | Definition |
|---|---|---|
Reliability (The degree to which the measurement is free from measurement error) | Internal consistency | The degree of the interrelatedness among the items |
Reliability | The proportion of the total variance in the measurements which is due to ‘true’ differences between patients | |
Measurement error | The systematic and random error of a patient’s score that is not attributed to true changes in the construct to be measured | |
Validity (The degree to which an instrument measures the construct(s) it purports to measure) | Content validity (including face validity) | The degree to which the content of an instrument is an adequate reflection of the construct to be measured |
Construct validity (including structural validity, hypothesis testing, cross-cultural validity) | The degree to which the scores of an instrument are consistent with hypotheses (for instance, with regard to internal relationships, relationships to scores of other instruments or differences between relevant groups) based on the assumption that the instrument validly measures the construct to be measured | |
Criterion validity | The degree to which the scores of an instrument are an adequate reflection of a ‘gold standard’ | |
Responsiveness | Responsiveness | The ability of an instrument to detect change over time in the construct to be measured |