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Table 2 COSMIN recommended criteria for good measurement properties

From: Measuring women’s experiences of maternity care: protocol for a systematic review of self-report survey instruments

Measurement propertyRatingCriteria
Structural validity+Classical Test Theory (CTT)
Confirmatory factor analysis: Comparative Fit Index or Tucker Lewis Index or comparable measure > 0.95 OR root mean square error of approximation < 0.06 OR standardised root mean residuals < 0.08
Item Response Theory (IRT)/Rasch
No violation of unidimensionality: Comparative Fit Index or Tucker Lewis Index or comparable measure > 0.95 OR root mean square error of approximation < 0.06 OR standardised root mean residuals < 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: χ2 > 0.001
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+At least low evidence for sufficient structural validity AND Cronbach’s alpha(s) ≥ 0.70 for each unidimensional scale or subscale
?Criteria for ‘At least low evidence for sufficient structural validity’ not met
At least low evidence for sufficient structural validity AND Cronbach’s alpha(s) < 0.70 for each unidimensional scale or subscale
Reliability+Interclass Correlation Coefficient (ICC) or weighted kappa ≥ 0.70
?ICC or weighted kappa not reported
ICC or weighted kappa < 0.70
Measurement error+Smallest detectable change (SDC) or limits of agreement (LoA) < minimal important change (MIC)
?MIC not defined
SDC or LoA > MIC
Hypotheses testing for construct validity+The result is in accordance with the hypothesis
?No hypothesis defined (by the review team)
The result is not in accordance with the hypothesis
Cross-cultural validity/measurement invariance+No important differences found between group factors (e.g. age and language) in multiple group factor analysis OR no important differential item functioning (DIF) for group factors (McFadden’s R < 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 area under the curve (AUC) ≥ 0.70
?Not all information for ‘+’ reported
Correlation with gold standard < 0.70 OR AUC < 0.70
Responsiveness+The result is in accordance with the hypothesis OR AUC ≥ 0.70
?No hypothesis defined (by the review team)
The result is not in accordance with the hypothesis OR AUC < 0.70