A collective decision was made to change the

numbering of the levels, such that normality is awarded a score of 0.) The association between the UCEIS (including the descriptors and the 2 alternative scoring methods) and the evaluation of overall endoscopic severity by the VAS was quantified using Pearson correlation coefficients. Specifically, each investigator’s responses for their set of videos were correlated with the mean overall severity (VAS) for those videos, where video means were computed using the responses of all other investigators. These correlations were summarized by median, minimum, and maximum across investigators. Statistical significance LDK378 clinical trial was assumed at a level of 0.05 without adjusting for multiple comparisons. Cronbach’s coefficient α, using partial correlation coefficients, was calculated for the overall UCEIS score and for the score with one-at-a-time descriptor deletion to evaluate internal consistency in the UCEIS.9 Intrainvestigator and interinvestigator agreements for descriptors and the overall UCEIS score were characterized by κ statistics, qualitatively interpreted by Landis and Koch.10

The standard κ summarizing the exact level of agreement was used for the descriptors. Because the overall UCEIS score represents a 9-level ordinal scale, a weighted κ was used, taking into account close agreement by assigning a weight of 1 for exact agreement, PI3K Inhibitor Library 0.5 for scores that differed by 1 level, and 0 otherwise. Interobserver κ values were calculated by stratifying by investigator pairs and using the common videos they scored but excluding the second scoring of duplicate videos. An average of investigator-pair κ values

(“overall κ”) was calculated, where the weighting was the inverse of their variance. Intraobserver and interobserver agreement between the overall evaluation of endoscopic severity on the VAS and the UCEIS was assessed by reliability Aldehyde dehydrogenase ratios (also known as intraclass correlation coefficients), estimated using mixed-effect linear models. The reliability ratios for interinvestigator agreement were estimated using a model with terms for “investigator,” “video,” and “error”; additional terms for “investigator-by-video effects” were used to evaluate intrainvestigator agreement.9 Correlation between the UCEIS and overall severity on the VAS, and all interobserver analyses avoided data from the second read of duplicate videos between investigators, and all those where clinical details were provided. Intraobserver analyses, including those for clinical detail/no clinical detail pairs, only used data from duplicate videos. The impact of knowledge of clinical details was evaluated by comparing UCEIS scores and overall severity scores on the VAS within the 50 clinical details/no clinical details pairs. Simple and absolute differences were computed within each pair.