by Jim Glass
Two earlier posts here covered the subject of how team records in one-sided games – "Big Wins" and "Big Losses" – can be a much better predictor of future performance than overall won-lost record, or even Pythagorean expectation – particularly when predicting performance in the playoffs.
Define a Big Win/Big Loss as being by 10+ points, treat all other games as ties (half a win), and compute each team's "BigWin%". The concept is that the result will be a better indicator of true team strength than regular W-L percentage. The inspiration for this idea was a post on this site showing that nearly half of all NFL game outcomes are determined by luck. It is reasonable to assume that most of those games are the closest games where a few chance events can tip the outcome – so if those close games are treated as ties (the median point differential in NFL games is about 10 points) the "noise" injected by chance into regular W-L records will be largely eliminated, giving a truer picture of team strength. The statistical record backs this up.
The playoff record
To recap what's been reported here earlier at greater length...
In the 15 years from 1995 through 2009, exactly 100 teams made the playoffs with a record of 11-5 or better. Of these:
* The top 37 teams by normal regular season W-L, with records of 13-3 or better (total: 497-95, 84%) produced in the playoffs a record of 43-31, a 58% winning percentage (with six Super Bowl winners, 16% of the 37 teams).
* The top 30 teams by Pythagorean expectation – based on points for-against ratio, and well-proven as predicting future W-L more accurately than past W-L – won the same 43 playoff games and lost only 23, a better 65% winning record (with seven Super Bowl winners, 23% of the 30).
* It took only the top the 24 teams by BigWin% to collect the same 43 playoff victories, against only 15 losses, an even better 74% winning percentage (with nine Super Bowl winners, 38% of the 24).
What about the teams that showed superior "clutch" character by winning the most close games during the regular season (as in "great teams win close games")?
* It took the 45 teams with the most "close wins" (by 10 points or less) during the regular season to win 43 playoff games, while losing 42, only a 50.6% winning percentage. (With three Super Bowl winners, 7% of the 45 teams). The nine best teams at winning close games, each with nine or more close wins during the regular season, went 8-9 in the playoffs.
OK, so much for recapping. (Anyone interested in more details can see the original post.)
Final 2010 ratings
I should have sent this in this last week, but family emergencies prevented. Life is full of conflicting priorities and hard decisions ("Should I take the wife to the hospital or finish the ratings? ... take the wife to the hospital or finish the ratings? ... aw, if I don't take her I'll never hear the end of it ...")
So, belatedly, here are the final BigW% ratings for 2010. These are computed using a strength-of- schedule adjustment based on BigW%, so the "BigW" number for each team is that expected from playing the same league-average strength schedule. The last two columns give the average strength of each team's opposition and its rank among all.
|Rank||Team||BigW||BigL||PCT||SoS||Rank - SoS|
Some quick observations. By BigW%...
* The AFC East is the strongest division by far and its teams faced by far the toughest schedule, playing each other and a very tough out-of-division slate. The three toughest schedules were faced by Miami, Buffalo and New England, while the Jets played the fifth-toughest. (Buffalo and Miami aren't as bad as their regular W-L records look.)
* New England's W-L record this year is extra impressive because top-winning teams usually have easier-than-average schedules if only because they get out of having to play themselves twice. (New England gets to play Buffalo twice, Buffalo has to play New England twice.) But the Pats have compiled their 14-2 against very near the toughest schedule in the league.
* Green Bay is the most powerful team in the NFC, by a bunch.
* San Diego is the best team to miss the playoffs (and would be the second-strongest team in the NFC). Go Norv! Go!
* Atlanta, everybody's favorite team to talk about on this site, is genuinely good but not 13-3 good. The Falcons are an impressive 8-2 in close games – if you are impressed by close games, which BigW% isn't. However their +4 in Big Wins is very good and makes them #2 (if just a bit ahead of Chicago) in the NFC.
* It's an AFC year, with five of the top six and seven of the top eleven teams in the AFC.
"For entertainment purposes only"
What does all this mean for the playoffs? At this point I have no idea how differences in BigW% translate into point spreads. (And unless you are in Nevada or Atlantic City or somewhere else where sports gambling is legal, of course you wouldn't be interested in that anyhow.)
This means the only real "calls" to be made using BigW% are when the public (as evidenced by, say, the betting line) believes one team is best and will win outright, while BigW% says the other team is best and will win outright, so the spread isn't an issue.
How did BigW% perform by that standard, for entertainment purposes, over the wild-card game weekend?
* BigW% said Green Bay was better than Philadelphia outright, while the spread had the Eagles better outright. I had no qualms about entertaining my friends by telling them to, um, root for the Packers. 1-0.
* Seattle has as dreadful a record by BigW% as it does under any other rating system. I'd never have
* Kansas City got its 10 wins playing against the easiest schedule in the AFC according to BigW%, so it getting crushed by a clearly better team that played a much tougher schedule is hardly a shock.
* The Jets were somewhat stronger than Indianapolis by BigW%, but the Colts had offsetting home field advantage making the odds close. That's pretty much the same as the point spread indicated -- the Colts being 2-point favorites in Indianapolis indicates New York would have been about 4-point favorites in New Jersey. As I don't know how much home field advantage is worth by BigW%, I'd call this game for practical purposes a push, which is pretty much how it ended.
So I'd tally this up as BigW% being successfully entertaining to the extent of 1-0 plus leaning the right way twice and being neutral once in the three no-call games.
And that's the end of my last item on BigW% for this season.
Happy New Year to all, and may the gods of the playoff pools entertain you well, to the extent it is legal.