Table 1.
Psychometric Property | Criteria |
---|---|
Reliability | |
Internal consistency degree to which responses to all items on a scale are consistent [43] |
Calculated correlations for total scale and domains [44] - Cronbach's alpha (α) > 0.70 [42,44] - Kuder-Richardson 20 (KR-20) > 0.70 [42,44] |
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 | |
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] Content assessed by experts [42,44] Reported which aspects of the measure were revised [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] Reported proportions [44,50] - 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] - Effect size > 0.5 [42,44,50] |
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] |