Agreement and measurement properties of the interviewer-administered, self-completed and proxy‐reported versions of the Tigrinya EQ-5D-Y-5L in Ethiopia

Objective To assess measurement properties of self-complete (SC), interviewer-administered (IA), and proxy-report versions of EQ-5D‐Y-5L and to assess the degree of agreement in response between these versions. Methods SC, IA, and proxy-report were administered to children and adolescents with and without health conditions on two occasions, separated by either a 10-day interval (to assess test-retest reliability) or a one-month interval (to assess responsiveness). The SC and IA versions were administered in randomized order. Agreement and test–retest reliability assessed using Gwet’s agreement coefficient (Gwet’s AC) and intraclass correlation coefficient (ICC). Feasibility, known-group validity, and responsiveness were assessed using missing values, Kruskal-Wallis test, and standardized effect size (SES), respectively. Results A total of 644 child/parent dyads participated. Missing values were higher for SC, particularly among younger children aged 8–12 years (4.65%-11.63%). Agreement between EQ-5D‐Y‐5L versions ranged from moderate to almost perfect, with excellent test-retest reliability across all dimensions and EQ-VAS. The EQ-5D-Y-5L level sum score (LSS) significantly differentiated between known disease groups across all versions (SC: χ² = 285; IA: χ² = 273; Proxy-report: χ² = 232; all p < 0.01). Both SC and IA versions were responsive to change in health with a moderate SES in “worsened” and “improved” groups. Conclusion The substantial agreement and similar measurement properties between SC and IA versions suggest that IA could be used as an alternative approach for data collection when self-complete is not an option. Although the proxy-report version had acceptable measurement properties, they were inferior to the SC and IA versions.