the two diverge. BPI's Strength of Record rating has BYU at #27. But their BPI is #56. When comparing Strength of Schedules between BPI and Kenpom, BPI puts BYU's schedule at #79 whereas Kenpom has it at #22. That seems like a very drastic difference. (NET rating puts their SoS somewhere in the middle at #42).

If you look at individual teams on BYU's schedule, Kenpom has St. Mary's at #22; BPI has them at #36. Kenpom has San Francisco at #32, BPI has them at #53; Kenpom has Creighton at #47, BPI has them at #82; Kenpom has Utah St. at #71; Utah St. has them at #95

Regardless of who is more accurate, it's safe to say that BPI views BYU's opponents as being weaker than what Kenpom views them at, which seems to ulitimately be where the divergence between the two rankings occur. Perhaps that is because BPI discounts games that are seen as "outliers", and also weight games based on things like number of days of rest, whether an opponent had a player sitting out, and the distance travelled to the game. Also, BPI's rankings have some preseason projections baked in such as number of returning players, average recruiting rankings of the incoming class, etc. I understand why they do this, but I'm not sure how it would compare to other systems that may or may not have that sort of data still baked into their ratings.

At the end of the day, I think both data points are valuable and I'm a much bigger fan of looking at aggregate rankings between a large number of reputable ranking systems, but if I had to choose just one I would probably lean towards Kenpom between the 2 simply because it has held up quite well over time.