Definitions of the psychometric properties used in the selection criteria for included articles
| Domain | Measurement property | Example test statistic | Definition |
| Reliability | The consistency of a test or measurement, that is, how consistently a measure produces similar results with repeated measures over a short period of time or across assessors at the same time point. This can also be thought of as the correlation between observed scores across replications. | ||
| Test–retest reliability | Correlation coefficient | Correlation between scores from the same test from assessments conducted over a short time interval. | |
| Inter-rater reliability | kappa, Bland-Altman test | The extent to which independent assessors produce similar ratings in judging the same abilities or characteristics in the same target person at the same time. | |
| Internal consistency reliability | Cronbach’s alpha, alpha | Degree of interrelatedness among items on the same tool, that is, how well the items work together to provide information on an underlying construct. | |
| Validity | The degree to which the tool measures what it is supposed to measure, that is, the degree to which the tool reflects the underlying construct. | ||
| Content/face validity | The degree to which the content of the tool is adequate for the construct being measured, that is, assessing the extent to which a tool appears to reflect the underlying construct. | ||
| Concurrent/criterion validity | Correlation coefficient; regression estimate | The degree to which scores on one measurement tool are related to scores obtained at about the same point in time from another tool considered the gold standard. | |
| Convergent validity | Correlation coefficient; regression estimate | Evidence that scores on a test or measurement are associated with theoretically related measures or variables. | |
| Predictive | Correlation coefficient; regression estimate | Evidence that a score correlates with a variable that can only be assessed at some point after the test has been administered or the measurement made, for example, evidence that scores now are correlated with scores at a future time point. | |
| Structural validity (dimensionality) | Exploratory factor analysis: number of factors, eigen values Confirmatory factor analysis: model fit statistics such as Comparative Fit Index, root mean square error of approximation | The degree to which the scores of an assessment are an adequate reflection of the dimensionality of the construct to be measured. | |
| Invariance | The property when a scale or construct provides the same results across different samples, populations, settings or characteristics. | ||
| Measurement invariance over countries | Likelihood ratio χ2 statistic and p-value from freeing parameters across groups | The degree to which an assessment or construct provides the same results across separate samples in different countries. | |
| Measurement invariance over other groups | Likelihood ratio χ2 statistic and p-value from freeing parameters across groups | The degree to which an assessment or construct provides the same results across different groups. | |
All definitions are based on the APA Dictionary of Psychology.7