We provide comprehensive evidence concerning the impact of IFRS 8 on the quality of segmental information disclosed in the annual reports of the largest companies in the European Union. We also assess the impact of using fifteen alternative proxies of segment information quality divided into four dimensions (extensiveness, fineness, variability, and consistency). The empirical results reveal that changes, and the strength of these changes, following IFRS 8 are dependent upon the proxy used. Our results have substantial implications for both policy makers and academic researchers, which are related to the impact of the principle-based IFRS 8 and the measurement of segment information quality. [ABSTRACT FROM AUTHOR]