Below are ESPN's NFL Football Power Index rankings heading into Week 15. For an explanation of FPI and how it is created, please read this article.

As a reminder, NFL FPI is a forward-looking power rating designed to measure team strength and project performance going forward. In the simplest sense, FPI answers the question, “If two teams met on a neutral field, which one would win and by how many points?” Each team’s rating represents how many points above or below average it is, based on opponent-adjusted measures of offensive, defensive and special teams performance on a per-play basis. Subtracting any two teams’ ratings equates to a predicted point margin between those teams on a neutral field.

Like most power ratings, FPI looks beyond a team’s win-loss record to determine how it won its games and whom those wins came against. Therefore, FPI doesn’t care if Team A lost more games than Team B, or if Team A lost to Team B earlier in the season. Ultimately, FPI’s goal is to accurately predict games and season outcomes, and the rating is simply a means for those projections.

For more analytics content, head to ESPN's analytics page.