Stroke; a journal of cerebral circulation
-
The modified Rankin scale (mRS) is the most commonly used outcome measure in stroke trials. However, substantial interobserver variability in mRS scoring has been reported. These studies likely underestimate the variability present in multicenter clinical trials, because exploratory work has only been undertaken in single centers by a few observers, all of similar training. We examined mRS variability across a large cohort of international observers using data from a video training resource. ⋯ Our results confirm interobserver variability in mRS assessment. The heterogeneity across countries is intriguing because it appears not to be related solely to language. These data highlight the need for novel strategies to improve reliability.