Table 1.

Criteria for good measurement properties according to the checklist [29]

Measurement property	Ratinga	Criteria
Structural validity	+	CTT: CFA: CFI or TLI or comparable measure > 0.95 OR RMSEA < 0.06 OR SRMR < 0.08b IRT/Rasch: No violation of unidimensionalityc: CFI or TLI or comparable measure > 0.95 OR RMSEA < 0.06 OR SRMR < 0.08 AND no violation of local independence: residual correlations among the items after controlling for the dominant factor < 0.20 OR Q3’s < 0.37 AND no violation of monotonicity: adequate looking graphs OR item scalability > 0.30 AND adequate model fit: IRT: χb > 0.01 Rasch: infit and outfit mean squares ≥ 0.5 and ≤ 1.5 OR Z‐ standardized values > ‐2 and < 2
	?	CTT: Not all information for ‘ + ’ reported IRT/Rasch: Model fit not reported
	-	Criteria for ‘ + ’ not met
Internal consistency	+	Criteria for “At least low evidenced for sufficient structural validitye “ not met
	?	Criteria for “At least low evidenced for sufficient structural validitye “ not met
	-	At least low evidenced for sufficient structural validitye AND Cronbach’s alpha(s) < 0.70 for each unidimensional scale or subscalef
Reliability	+	ICC or weighted Kappa ≥ 0.70
	?	ICC or weighted Kappa not reported
	-	ICC or weighted Kappa < 0.70
Measurement error	+	SDC or LoA < MICe
	?	MIC not defined
	-	SDC or LoA > MICe
Hypotheses testing for construct validity	+	The result is in accordance with the hypothesisg
	?	No hypothesis defined (by the review team) The result is not in accordance with the hypothesisg
	-	The result is in accordance with the hypothesisg
Cross‐cultural validity\measurement invariance	+	No important differences found between group factors (such as age, gender, language) in multiple group factor analysis OR no important DIF for group factors (McFadden’s Rb < 0.02)
	?	No multiple group factor analysis OR DIF analysis performed
	-	Important differences between group factors OR DIF was found
Criterion validity	+	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
	-	Correlation with gold standard ≥ 0.70 OR AUC ≥ 0.70
Responsiveness	+	The result is in accordance with the hypothesisg OR AUC ≥ 0.70
	?	No hypothesis defined (by the review team)
	-	The result is not in accordance with hypothesisg or AUC < 0.70

AUC area under the receiver operating characteristic curve, CFA confirmatory factor analysis, CFI comparative fit index, CTT classical test theory, DIF differential item functioning, ICC intraclass correlation coefficient, IRT item response theory, LoA limits of agreement, MIC minimal important change, RMSEA root mean square error of approximation, SEM standard error of measurement, SDC smallest detectable change, SRMR standardized root mean residuals, TLI Tucker‐Lewis index

^a“ + “ = sufficient, “ – “ = insufficient, “? “ = indeterminate

^bTo rate the quality of the summary score, the factor structures should be equal across studies

^cunidimensionality refers to a factor analysis per subscale, and structural validity refers to a factor analysis of a (multidimensional) patient‐reported outcome measure

^dAs defined by grading the evidence according to the GRADE approach

^eThis evidence may come from different studies

^fThe criterion Cronbach alpha < 0.95 was deleted because this is relevant in the development phase of a PROM but not when evaluating an existing PROM

^gThe results of all studies should be taken together and then decided if 75% of the results are in accordance with the hypotheses