NFL Forecaster Accuracy Correlations To predict the winners of football games, the opposing teams must be ranked. A number of elements may be taken into account, including yards gained passing and rushing, average yards per down, and quarterback ranking. However, only two things really matter: (1) a team's win/loss record which in turn depends upon (2) the number of points scored by and against that team. A winning team must win games and to do so it must score more points than its opponent. The correlations for 24 seasons between Forecaster's ranking system and the teams' offenses, defenses (determined by points) and win-loss-tie percentages are quite strong. Teams' W-L-T % Avg # Points Scored By The Teams Per Game +0.811 Teams' W-L-T % Avg # Points Scored Against The Teams Per Game -0.795 Teams' W-L-T % Avg of Forecaster's "Total" Ranking +0.979 Using only scores, NFL Forecaster assigns each NFL team an offense and defense ranking and a total ranking. Based on these rankings Forecaster predicts winners of games and the point spreads. Year-By-Year Accuracy for 24 Seasons     Games Wins Spreads   Games Predicted Correctly Correctly Season Predicted Even Predicted Predicted 1984-85 190 34 60% 56% 1985-86 197 27 61% 57% 1986-87 209 15 70% 61% 1987-88 193 17 59% 52% 1988-89 214 10 62% 51% 1989-90 214 10 65% 58% 1990-91 218 6 65% 55% 1991-92 210 14 74% 66% 1992-93 210 14 68% 59% 1993-94 198 26 64% 54% 1994-95 203 21 62% 51% 1995-96 217 23 64% 57% 1996-97 214 26 65% 56% 1997-98 225 15 62% 51% 1998-99 226 14 71% 63% 1999-00 228 20 66% 56% 2000-01 223 25 65% 58% 2001-02 234 14 65% 56% 2002-03 235 21 61% 55% 2003-04 239 17 67% 55% 2004-05 239 17 64% 58% 2005-06 234 22 69% 60% 2006-07 230 26 59% 50% 2007-08 236 20 66% 59% 24-Yr Avgs 92% 8% 65% 57% Removing the unusual 1987-88 strike season from consideration raises Forecaster's wins and spreads accuracy about 0.3%. Wins/Spreads Accuracy for 24 Seasons When Forecaster predicted a spread of It correctly predicted the winner It correctly predicted the spread 1 53% 53% 2 60% 58% 3 63% 58% 4 66% 54% 5 75% 56% 6 76% 62% 7 78% 57% 8 84% 57% 9 77% 53% 10 to 12 86% 53% 13 to 15 93% 64% All Spreads/All Games 65% 57% Forecaster's ability to predict winners and spreads is always better than 50/50. There are, of course, seasonal fluctuations. For example, for the 1996-97 season Forecaster predicted winners by 6 points with 100% accuracy but with only 60% accuracy for the 1993-94 season. NFL Forecaster takes into account home-team advantage. However, it gives every home team the same advantage. It does not keep track of a team's win-loss record at home and away and give it a pro-rated advantage (positive or negative) for playing at home. That is, Forecaster uses only scores to rank teams and it ranks them objectively. Therefore, it cannot take into account that the particular team is very good on Monday night or that a quarterback broke his arm during practice, but you can. NFL Forecaster's help file topic "Interpreting Forecasts" contains much more information.

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