VALIDATION DATA

MEASUREMENT PROPERTIES
Limitations >=5 European languages (English)
Observations
1. RELIABILITY
A. Internal Consistency Tested
Cronbach's (Describe)

Cronbach’s alpha = 0.925

B. Reliability intraobserver or test-retest Tested
Continuous scores: intraclass
correlation coefficient (ICC)
Dichotomus: Cohen kappa (Describe)

Test-retest showed moderate agreement for all questions when comparing baseline and the first follow-up (kappa 0.54-0.65) and greater consistency between the two follow-up questionnaires (kappa 0.65-0.75). 

C. Reliability interobserver or Measurement error Not Tested
Standard error of measurement (SEM),
smallest detectable change (SDC) or
Limits of agreement (LoA) (Describe)
2. VALIDITY
A. Content validity: face validity Tested
Expert opinion (relevance and
comprehensiveness) (Describe)

Content validity was investigated using the proportion of participants that had missing responses, and that gave “not applicable” responses based on the assumption that they perceived these items/questions not to be relevant.

Most participants did not use the response “not applicable”. For all participants, between 5 and 22 (0.9–3.8%) gave a “not applicable” response to at least 1 of the 6 PEI questions.

B. Construct Validity:
Structural validity
Tested
Hypotheses-testing Tested
Cross-cultural validity Tested
Brief Description

CFA showed the 1-factor PEI model had approximate fit to the data for all 4 groups, with all SRMR values < 0.08, and standardized residual correlations were  small (< 0.10, with 2 exceptions that were close to 0.10). This supports the construct validity of the PEI.

C. Criterion validity Not Tested
Comparison with a 'gold standard' Continuous scores:
correlations, ROC curves Dichotomus:
Sensitivity & Specificity (Describe)