It is based on the Elo rating system but includes modifications to take various football-specific variables into account, like the margin of victory, importance of a match, and home field advantage.
In 1997, Bob Runyan adapted the Elo rating system to international football and posted the results on the Internet.
[2] The FIFA World Rankings is the official national teams rating system used by the international governing body of football.
[6] The major difference between the World Football Elo Rating and the new men's FIFA rating system is that the latter does not consider goal differential and counts a penalty shoot-out as a win/loss rather than a draw (neither method distinguishes a win in extra time from a win in regular time).
[7] The same example of a three-team friendly tournament on neutral territory is used as on the FIFA World Rankings page.
The next table illustrates how the points would be divided following the same results as above, but with two roughly equally ranked teams, B and C, being involved: