What is the biggest difference between the ESPN SPI and FIFAs rankings?
• SPI uses detailed “competitiveness coefficients” based on lineups and rosters to assess the true quality and importance of particular matches. • SPI uses a flexible “assessment period” — we don’t need to go as far back in time to rate teams that play more frequently. • SPI uses an advanced, iterative calculation of opponent strength — similar to those used by superior college basketball and college football ratings systems — rather than assigning arbitrary continent coefficients as other systems such as FIFA’s do. • SPI creates separate ratings for offense and defense. • SPI accounts for goal differential. • SPI accounts for home-field advantage. • SPI’s ratings are intended explicitly to be forward-looking and predictive; other ratings systems may have different objectives. • SPI evaluates how a team’s players performed in club play as well as international play. Nate Silver is a contributor to ESPN.com and ESPN the Magazine, and is an author of Baseball Prospectus.
