Table 1 Summary of psychometric properties and criteria used to review measures.
Psychometric Property | Criteria |
|---|---|
Reliability | Â |
Internal consistency   degree to which responses to all items on a scale are consistent [43] | Calculated correlations for total scale and domains [44] |
Test-retest   reproducibility of scores on a scale over repeated administrations [44] | Second administration within 2-14 days [46] Calculated correlations for total scale, domains and items [47]   - Cohen's kappa coefficient (κ) > 0.60 [44]   - Pearson correlation coefficient (r) > 0.70 [42, 44]   - Intraclass correlation coefficient (ICC) > 0.70 [42, 44] |
Validity | Â |
Face     subjective assessment of whether a scale 'appears' to measure what it is designed to measure [43] | Assessed as reasonable by those who administer/complete it [43] |
Content     degree to which the content of a scale is representative of the issue being measured [43] | Reported item selection process [42, 44] |
Construct     way in which the internal structure of a scale relates to other conceptual constructs [44] | Stated hypothesis about correlations between measures [44]     - Convergent (r) > 0.40 or Divergent (r) < 0.30 [48] Calculated correlations between known-groups [42] Performed factor analysis [44]     - Eigenvalues > 1 [49] |
Criterion   how well a scale agrees with existing "gold standard" measurement of the same issue [44] | Provided rationale for "gold standard" measure [44] Stated type of criterion validity (concurrent or predictive) [43]     - Sensitivity - % with issue correctly classified [44, 50]     - Specificity - % without issue correctly classified [44, 50] |
Responsiveness   sensitivity of a scale to detect clinically important change in an outcome or behaviour over time [42, 50] | Reported floor/ceiling effects [51] - < 5% of respondents have highest or lowest score [51] Reported magnitude of change [42] |
Acceptability   level of burden placed on those who complete the measure [42] | Reported response rate, missing items, reading level, time to complete [42] |
Feasibility   level of burden placed on those who administer the measure [42] | Reported perceived time to administer, score, interpret [42] |
Cross-cultural adaptation   conceptually, linguistically equivalent and display similar psychometric properties to the original form [42] | Confirmed reliability and validity reflects the original version [42] |