In this blog, I will focus on the NFL Ranking based on the ELO algorithm that Nate Silver’s FiveThirtyeight uses. The guys at 538 have done a good job.The ELO and NFL ranking was part of my workshop at the Global Big Data Conference this Sunday. The full presentation is in slideshare.
ELO – the algorithm made famous by Facebook & depicted in the movie Social Network
The k-Factor is the main leverage point to customize the algorithm for different domains.
- For example Chess has no notion of a season; Soccer,Football & Basket ball are dependent on seasons – teams change during different seasons
- Chess has no score to consider except WIn,Lose or Draw; but ball games have scores that need to be accommodated
- For Chess k=10; for soccer it varies from 20 to 60; 20 for friendly matches to 60 for World Cup Finals
- As we will see later, NFL adjusts k with the Margin Of Victory Multiplier
- NFL also adjusts k to weigh recent games more heavily, w/ exponential decay
- There are also mechanisms for weighing playoffs higher than regular season games (We will see this in Basketball)
538’s take on ELO
NFL 2014 Predicts & Results
The R program ELO-538.R is in Github
2014 Ranking Table
- Exponential decay with more weight for recent games – later in the season
- Calculate the rankings from 1940 to present, draw graphs like this from 538