Additional File 2. Definition of Psychometric Properties According to Terwee Et Al., 24

Additional file 2. Definition of psychometric properties according to Terwee et al., [24]

Psychometric property Definition Criteria for scoring the psychometric properties Internal Consistency “The extent to which items in a Factor analyses performed on (sub)scale are intercorrelated, adequate sample size AND thus measuring the same Cronbach’s alpha(s) calculated construct” per dimension AND Cronbach’s alpha(s) between 0.70 and 0.95; Content validity “The extent to which the A clear description is provided of domain of interest is the measurement aim, the target comprehensively sampled by the population, the concepts that are items in the questionnaire” being measured, the item selection and who were involved in item selection (i.e. investigators OR experts) Criterion validity “The extent to which scores on Convincing arguments that gold a particular questionnaire relate standard is ‘‘gold’’ AND to a gold standard” correlation with gold standard >0.70; Construct validity “The extent to which scores on Specific hypotheses were a particular questionnaire relate formulated AND at least 75% of to other measures in a manner the results are in accordance with that is consistent with these hypotheses theoretically derived hypotheses concerning the concepts that are being measured” Reproducibility a. Agreement “The extent to which the scores Convincing arguments that on repeated measures are close to agreement is acceptable. each other (absolute measurement error)” b. Reliability Test-retest Reliability “The extent of agreement across ICC or Kappa >0.70 two administrations of a test, assuming nothing happened between testings (like treatment or other change-producing event).” Inter-rater Reliability “The extent of agreement ICC or Kappa >0.70 among two or more raters at a single testing session.” ICC = intraclass correlation coefficient