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Table 1 Updated criteria for good measurement properties by Prinsen et al. [60]

From: Imagery ability assessments: a cross-disciplinary systematic review and quality evaluation of psychometric properties

Measurement property

Rating

Criteria

Structural validity

+

CTT

CFA: CFI or TLI or comparable measure > 0.95 OR RMSEA < 0.06 OR SRMR < 0.08a

IRT/Rasch

No violation of unidimensionalityb: 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: χ2 > 0.001

Rasch: infit and outfit mean squares ≥ 0.5 and ≤ 1.5 OR Z-standardised 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 evidencec for sufficient structural validityd

AND Cronbach’s alpha(s) ≥ 0.70 for each unidimensional scale or subscalee

?

Criteria for “At least low evidencec for sufficient structural validityd” not met

At least low evidencec for sufficient structural validityd AND Cronbach’s alpha(s) < 0.70 for each unidimensional scale or subscalee

Reliability

+

ICC or weighted Kappa ≥ 0.70

?

ICC or weighted Kappa not reported

ICC or weighted Kappa < 0.70

Measurement error

+

SDC or LoA < MICd

?

MIC not defined

SDC or LoA > MICd

Hypotheses testing for construct validity

+

The result is in accordance with the hypothesisf

?

No hypothesis defined (by the review team)

The result is not in accordance with the hypothesisf

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 R2 < 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

Responsiveness

+

The result is in accordance with the hypothesisf OR AUC ≥ 0.70

?

No hypothesis defined (by the review team)

The result is not in accordance with the hypothesisf OR AUC < 0.70

  1. The criteria are based on Terwee et al.  [59]
  2. AUC Area under the 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, SDC Smallest detectable change, SRMR Standardised root mean residuals, TLI Tucker–Lewis index
  3. ‘+’ sufficient, ‘-‘ insufficient, ʻ?ʼ indeterminate
  4. aTo rate the quality of the summary score, the factor structures should be equal across studies
  5. bUnidimensionality refers to a factor analysis per subscale, while structural validity refers to a factor analysis of a (multidimensional) Patient-Reported Outcome Measure
  6. cAs defined by grading the evidence according to the GRADE approach
  7. dThis evidence may come from different studies
  8. eThe criteria ‘Cronbach alpha < 0.95’ was deleted, as this is relevant in the development phase of a PROM and not when evaluating an existing PROM
  9. fThe results of all studies should be taken together and it should then be decided if 75% of the results are in accordance with the hypotheses