| MEASUREMENT PROPERTIES | |
| Limitations | <5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Internal consistency was acceptable for the 3 components of productivity cost, with an inter-item correlation ranging from 0.42 to 0.62. |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
The intraclass correlation coefficient values ranged from 0.88 to 0.99 for all items except one; kappa ranged from 0.61 to 0.92, indicating overall good reliability of the questionnaire. |
| C. Reliability interobserver or Measurement error | Not Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
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| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
It was created based on previously validated questionnaires; the questions in the iPCQ are based on the Short Form- Health and Labour Questionnaire (SF-HLQ), the Productivity and Disease Questionnaire (PRODISQ) and the QQ method. The questionnaire was feasible, with little missing data and no floor or ceiling effects. Content validity displayed good comprehensibility and relevance and sufficient comprehensiveness. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description |
The iPCQ was expected to cover the 3 components of productivity costs: absenteeism, presenteeism, and unpaid work productivity costs. To confirm the underlying structure of the questionnaire and to investigate structural validity of the iPCQ, confirmatory factor analysis was conducted. Factor analysis revealed a 3-component solution accounting for 82% of the total variance; items loaded as expected and supported the original structure of the iPCQ. |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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