Table 1 Quality criterion for measurement properties adapted from COSMIN manual for systematic reviews of PROMS (Prinsen et al., [17])
Psychometric property | Rating | Quality criteria |
|---|---|---|
Internal consistency | + | Cronbach’s alpha(s) ≥ 0.80 |
? | Cronbach’s alpha not determined or dimensionality unknown | |
- | Cronbach’s alpha (s) < 0.80 | |
Reliability | + | ICC/weighted kappa ≥ 0.70 or Pearson’s r ≥ 0.80 |
? | Neither ICC/weighted kappa, nor Pearson’s r determined | |
- | ICC/weighted kappa < 0.70 or Pearson’s r < 0.80 | |
Content validity | + | Process was described to consider how each item is relevant to the construct. All items are considered to be comprehensible, for the target population, and for the purpose of the measurement and the questionnaire is considered to be comprehensive |
? | Not enough information available; no research | |
- | No process described for analysis or not all items are considered to be relevant, comprehensible or comprehensive for the construct measured | |
Structural validity | + | EFA: Factors should explain at least 50% of the variance CFA: RMSEA ≤ 0.06, CFI or TLI ≥ 0.95 |
? | Explained variance not mentioned | |
- | EFA: Factors explain < 50% of the variance; CFA: RMSEA > 0.06, CFI or TLI < 0.95 | |
Convergent validity | + | Relationship has been examined between scale scores and similar constructs using multi-trait multi method matrix, latent variable modeling, or Pearson’s product moment coefficient, correlation coefficient ≥ 0.70 |
? | Not enough information available | |
- | Correlation with another scale measuring the same construct < 0.70 |