Comparing Powerwise (PWR) and the NCAA Power Index (NPI): Advising the NCAA Men's Division I Lacrosse Committee

TL;DR

This paper compares two ranking methods, PWR and NPI, for NCAA team sports, finding PWR more suitable for sports with wider victory margins like lacrosse.

Contribution

It provides a detailed comparison of PWR and NPI, highlighting PWR's advantages for ranking sports with larger victory margins.

Findings

NPI is less suitable for sports with wider victory margins

PWR outperforms NPI in accuracy and stability

The memo discusses differences in objectivity and reproducibility

Abstract

This memo compares two methods, Powerwise (PWR) and the NCAA Power Index (NPI), that aim to rank NCAA Division I, II, and III teams on the basis of deservedness of an invite to end-of-season championship tournaments. It find that while the NPI might be a fit for sports like hockey, it falls short of the PWR method for use in ranking team sports that regularly feature somewhat wider margins of victory, including football, basketball, and lacrosse. In comparing the methods, this memo highlights differences in i) accuracy; ii) procedural integrity; iii) objectivity; iv) reproducibility; v) simplicity; and vi) stability; before drawing conclusions.