Xavier is 50th in the KenPom. While the NCAA tournament consists of 68 teams, the savvy watcher knows that the split between at-large and auto bids means that the cut line for auto bids is somewhere around the mid 40s. That spells trouble for Xavier, or it would if the bracket was filled according to the KenPom rankings.
It isn't. While KenPom and metrics like it are based on the process whereby teams perform, the actual committee is all about results, and Xavier's results have been good.
Bart Torvik calculates Wins Above Bubble (WAB) on his eponymous site.