Friday, January 28, 2011

Sports Myths : Defense wins championship

I am sure, like me, you have heard a million times : " Offense wins games, Defense wins Championships". The problem is, that statements does not actually hold up.

A neat sabermetrics statistic, can predict the winning percentage of a team by using a fancy formula. The surprising thing is that this formula works accross sports. The same formula WP = (Runscored*Runsagainst) / ((RS^2)+(RA^2) , works for Hockey but with goals. Sadly the formula does not work for American Football. I am not entirely sure why this is the case, but the fact of the matter is true.

Then there must be some linear weights that one can assign to Points For and Points Against, right? Well the first thing i did was run a correlation of the two fields against the amount of wins a Team gets over a reason.

Points for (r value) = .766496
Points against = -.26189

Now this makes sense a little, and i'll do my best to explain this. The negative number means that as points against goes up, meaning a team starts giving up more points, their total (and chances of) wins goes down. While points for means the opposite, the more points the more total wins the team will have. This is logical right? Well, the next thing is not so obvious, its the degrees of those values. The Points for is way more associated with victory than points against, meaning that scoring points is a lot more important to winning than giving up points, those are just merely secondary.

I am sure some of you are reading and saying "What about Playoffs?", teams that cant hold their opponents clearly lose games in the playoffs. That statement is actually false. Over the last 10 years, the teams with the better offense and worse defense won 75% of the games. Shocking i know, but teams that score a lot more have a better chance of winning the game than those who stop the other team from scoring*. Now there is on exception to this rule, the Pittsburgh Steelers. The Steelers are the only team in the last 10 years to win with a better defense, and not a better offense.

All in all, Championships are not made by defenses, they are indeed won by Offenses, the people that do the scoring.

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