Table 13 Results of studies assessing measurement invariance of the instruments included in the review
Instrument | N | Mean Age (SD) | % female | Country | Analysis model | Key result(s) | Rating of measurement property | |
|---|---|---|---|---|---|---|---|---|
Rating | Quality of evidence | |||||||
ZBI [60] | 475 | 44 (NR) | 81 | UK, US | ANOVA (DIF) | “Analysis of scale stability showed that there was no significant uniform differential item functioning (i.e., a systematic difference across the full range of level of burden) or nonuniform differential item functioning (i.e., nonuniformity in the differences across level of burden) by country (UK vs. US; p > 0.002 and p > 0.009) or by sex (female vs. male; p > 0.004 and p > 0.028).” | + | Very low |