Table 1.
Definitions of Measurement Properties of Instruments Assessed by COSMIN Checklist
| Measurement Property | Definition |
|---|---|
| Internal Consistency | The degree of the interrelatedness among the items; the extent to which scores for patients who have not changed are the same using different sets of items from same instrument |
| 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 |
| Content Validity | The degree to which an instrument measures the construct(s) it purports to measure; the degree to which the content of an instrument is an adequate reflection of the construct to be measured |
| Structural Validity | The degree to which the scores of an instrument are an adequate reflection of the dimensionality of the construct to be measured |
| Hypothesis Testing | 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; Idem construct validity |
| Cross-cultural | Validity The degree to which the performance of the items on a translated or culturally adapted instrument are an adequate reflection of the performance of the items of the original version of the instrument |
| Criterion Validity | The degree to which the scores of an instrument are an adequate reflection of a ‘gold standard’ |
| Responsiveness | The ability of an instrument to detect change over time in the construct to be measured; Idem responsiveness |
Adapted from the COSMIN Checklist Manual (v9)1
1
Mokkink LB, Terwee CB, Patrick DL, et al. The COSMIN study reached international consensus on taxonomy, terminology, and definitions of measurement properties for health-related patient-reported outcomes. Journal of Clinical Epidemiology. 2010 Jul;63(7):737-45. PMID: 20494804.