Table 1.

List of the domains and measurement properties, definition, and quality criteria according to the COSMIN guideline

Domain	Measurement property	Definition	Quality criteria
Validity		The degree to which a PROM measures the construct(s) it purports to measure
	Content validity	The degree to which the content of a PROM is an adequate reflection of the construct to be measured	Not applicable
	Construct validity (hypothesis testing)	The degree to which the scores of a PROM 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 PROM validly measures the construct to be measured	(+) The result is in accordance with the hypothesis (?) No hypothesis defined (by the review team) (−) The result is not in accordance with the hypothesis
	Criterion validity	The degree to which the scores of a PROM are an adequate reflection of a ‘gold standard’	(+) Correlation with gold standard ≥ 0.70 OR AUC ≥ 0.70 (?) Not all information for ‘+’ reported (−) Correlation with gold standard < 0.70 OR AUC < 0.70
Reliability		The degree to which the measurement is free from measurement error
	Reliability	The proportion of the total variance in the measurements which is due to ‘true’† differences between patients	(+) ICC or weighted Kappa ≥ 0.70 (?) ICC or weighted Kappa not reported (−) ICC or weighted Kappa < 0.70
	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	(+) SDC or LoA < MIC (?) MIC not defined (−) SDC or LoA > MIC
Responsiveness		The ability of a PROM to detect change over time in the construct to be measured	(+) The result is in accordance with the hypothesis7 OR AUC ≥ 0.70 (?) No hypothesis defined (by the review team) (−) The result is not in accordance with the hypothesis7 OR AUC < 0.70
	Responsiveness
Interpretabilitya		Interpretability is the degree to which one can assign qualitative meaning—that is, clinical or commonly understood connotations—to a PROM’s quantitative scores or change in scores	Not applicable

Definitions and quality criteria are in accordance to the COSMIN guideline (Prinsen, 2018 Quality of Life Research)

COSMIN COnsensus‐based Standards for the selection of health Measurement Instruments, PROM patient-reported outcome measure, AUC area under the curve, ICC intraclass correlation coefficient, SDC standard error of measurement, LoA limits of agreement, MIC minimal important change

(+): sufficient; (−): insufficient; (?): indeterminate

^aInterpretability is not considered a measurement property, but an important characteristic of a measurement instrument