Category Archives: Uncategorized
An analytic look at the 2013-2014 NBA season
The 2013-2014 NBA season is here. Is your team ready to outperform its expectation?
In this post, I aggregated several statistical or simulation-based predictions of each team’s regular season wins. The prediction sites or methods used included Team Rankings, Schoene (ESPN), Prediction Machine, and Box Score Geeks, and I compared these predictions against posted totals for team wins using sportsbetting.ag (which I’ll call the ‘Las Vegas line’).
First, here’s a look at the correlation between each site’s projected win totals. Team Rankings and Prediction Machine seem very similar to the Las Vegas posted win totals, with slightly higher deviations in the Schoene projection. The Box Score Geek projection system seems well off that of the other sites.
| Las Vegas Line | Schoene | Team Rankings | Prediction Machine | Box Score Geeks | |
| Las Vegas Line | 1.00 | 0.91 | 0.99 | 0.99 | 0.72 |
| Schoene | 0.91 | 1.00 | 0.89 | 0.90 | 0.75 |
| Team Rankings | 0.99 | 0.89 | 1.00 |
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College Football and Money
How can this be a serious statement?
Iowa State football coach Paul Rhoads received about $2 million, which included a performance bonus for taking his 6-7 team to the AutoZone Liberty Bowl and additional retention pay.
http://collegefootball.ap.org/article/coaches-academics-top-list-state-salaries
He got a bonus for going 6-7!
Cheers.
Against the Spread Woes: Part 2
This post was written jointly by Michael Lopez (@StatsByLopez) and Gregory J. Matthews (@StatsInTheWild).
In last week’s post, we showed that several of the larger statistically-inclined websites which offer NFL picks have had a rough go of it to start the season, at least as far as their picks against the spread. More surprisingly, these results come on top of a string of several successful seasons in which each site consistently posted winning (>50%) results.
Today, we dive in to explore why the sites may have fallen behind the 8-ball.
First, we allocated picks from Football Outsiders, numberFire, Team Rankings, and Prediction Machine, four of the websites that we discussed last week. While there are several other competing analytics sites worth mentioning (including Statsational, CFBMatrix, and Massey-Peabody, who have had decent seasons), we stuck with these four because they had readily available for several seasons going back in time, and/or because they pick all NFL games each weekend.
First, let’s see how often each site picks the home team to cover, and how often each picks the favorite to cover
|
Site |
Home team (%) |
Favorite (%) |
|
Football Outsiders |
52.1 |
43.6 |
|
numberFire |
42.1 |
42.7 |
|
Prediction Machine |
45.4 |
40.2 |
|
Team Rankings |
29.7 |
33.3 |
These results aren’t totally surprising; the public often backs favorites and home teams, leaving skilled betters to often choose underdogs or road teams. In fact, over at ESPN Insider, Dave Tuley touts a “dogs or pass” philosophy. Still, it’s noticeable that all four prediction sites tend to back underdogs, and most tend to favor the road team, at least through week 8.
Perhaps these numbers explain the poor performance through week 8, as home teams (55% ATS) and favorites (54% ATS) have cleaned up.
Next, we consider if the sites are similar with respect to their picks. The following cells indicate the percentage of picks in which the two sites (one on the row, the other on the column) have agreed on. Surprisingly, the websites appear to be using methods or algorithms which are independent of one another, with percentages around 50 indicating that whether or not each pair of sites agrees on a pick is more or less a coin flip.
|
Football Outsiders |
numberFire |
Prediction Machine |
Team Rankings |
|
|
Football Outsiders |
X |
58.7 |
55.3 |
47.9 |
|
numberFire |
58.7 |
X |
50.4 |
53.7 |
|
Prediction Machine |
55.3 |
50.4 |
X |
51.2 |
|
Team Rankings |
47.9 |
53.7 |
51.2 |
X |
Better yet, what if all four sites agree? Here are the frequencies, and cover percentages, based on the number of websites which backed the home team.
Number of sites picking the home team
|
4 |
3 |
2 |
1 |
0 |
|
|
Frequency (%) |
21 |
25 |
49 |
22 |
4 |
|
Home record (ATS) |
12-7-2 |
15-10 |
26-23 |
9-13 |
2-2 |
This suggests the sites are in complete harmony with respect to picking the road team, home picks are a healthy 12-7-2. Of course, those numbers are too small a sample to yield any statistically significant results.
Let’s now take a look at all the individual teams and see how the group as a whole has done for each. The table below show the total record against the spread for all four sites broken out for games involving that team. For instance, the four sites are 15-17-0 ATS when picking games involving the Chicago Bears while their picks are 17-11-0 ATS for the games with the Atlanta Falcons. It looks like these sites are having particular trouble with the Bears, Packers, Saints, 49ers and Titans. Most of the other records for each team are at or very near .500 with very few teams having a winning record. In fact, there are only 5 teams that these four sites in total have a winning record for so far this season: Falcons (17-11), Bills (18-14), Vikings (18-10), Patriots (18-14), and the Raiders (14-10-4). Is there any obvious common thread between these teams? Please leave serious and sarcastic suggestions in the comments.
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Next let’s separate out each site and look at winning percentages. The graph below shows a summary of winning percentages (ATS) for each site. Each wedge represents a team and the larger the wedge the higher the winning percentage. Each group of four plots represents a site. The divisions are labeled and the conferences are represented by blue and red wedges for the NFC and AFC, respectively. So, for instance, Number Fire is doing a really good job picking games against the spread involving NFC North opponents whereas there are not doing so well against the AFC North.
Finally, below are the results from each site that were used to generate the above image. No site has a perfect record with any team this year, but Football Outsiders is getting killed by Chicago (0-6-1) and the Saints (0-7). Though they aren’t the only ones being scorched by the Saints. White NumberFire is 4-3 with the Saints, TeamRankings and Prediction Machine are 1-6 and 3-4 respectively.
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Cheers.
Week 8 NFL Playoff Probabilities
Unless something nutty happens in the next eight weeks, we’re looking at exactly the NFC North and MAYBE if Carolina puts together some big games (that’s with games against the Saints and Pats, who both are in but are also tough teams…). But wait! Count those AFC teams that are hovering near 1.00 and you only find five teams (KC is hiding there just behind the Broncos.) So who will get the sixth playoff spot for the AFC? While it looks like a race to the bottom for the AFC East teams that aren’t the Pats, the Fins along with the Chargers, Titans, Ravens and Browns all have punchers’ chances at that last spot. This Sunday’s Browns vs Ravens match up and the Week 11 SD vs Miami game could both loom large.
I feel stupid for even saying this, but I think the second Wild Card will actually be a bit interesting. The probabilities in chart take into consideration remaining strength of schedule, but clearly it’s worth looking at it in some detail. The Chargers have two games against Denver and one against KC, but KC is week 17, and they get to play the Giants and Raiders. The Dolphins schedule isn’t too bad, they play the Bengals this week, and the Patriots again, but not until week 15 (though we know Belichick doesn’t let off the gas pedal), plus Carolina and SD. The rest of their schedule is light, with two games against the Jets (who have a nice saw-tooth win/loss/win pattern going, and if that pattern holds, they’d lose both games against the Dolphins*) , plus the BIlls, Steelers and Bucs. Baltimore has two left against Cincy (though one in week 17) plus the Bears, Lions, Pats with only the Vikings and the Steelers as absolute terrible opponent. The Browns have only one left against the Bengals, the Pats plus the Bears, while they have two against Pittsburgh and one against Jacksonville. They both play the Jets, so who know what will happen there.
* I do not think there is some magic pattern leading the Jets to an 8-8 season. I think it’s that they’re not a very good team.
I personally would think the the smart money is on the Titans. They have two games against the Colts and one against the Broncos, but they also have two against the Jags, and one each versus the Rams, the Raiders, the Texans, and the Cardinals, four teams who are demonstrably terrible.
Stick with us to see how the playoff picture unfolds. Do not stick with certain other sites, who (no lie) actually seem to think the Bengals week 7 49-9 win over the Jets is somehow going to make it harder for them to beat the Dolphins. Um…. sure.
NCAA Football Top 25 – 10/27/2013
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If you’ve used statistics websites for your NFL picks, you’ve been doing it wrong
It’s true. I am doing terrible in the NFL this year. But so is basically everyone else.
It’s still relatively early in the NFL season, but signs point to this being one of the worst seasons ever for simulation & statistics based predictors of game results. In fact, having followed several websites for the last few years, this is by far the worst I can remember each one doing as far as accuracy is concerned.
Here, I summarize results through week 7.
Football Outsiders (FO) : These guys have pretty much set the standard for NFL statistical analyses, as demonstrated by their preseason almanacs, appearances across the media, and downloadable spreadsheets with all sorts of good information. In their first five years of picking games against the spread (ATS), from 2008 to 2012, FO finished with yearly success rates of 53.7%, 51.2%, 56.1%, 52.0%, and 57.8%, respectively. There’s no public access for historical picks, but I’ve followed along and these numbers are 100% trustworthy.
This Fall, however…
View original post 606 more words
If you’ve used statistics websites for your NFL picks, you’ve been doing it wrong
It’s true. I am doing terrible in the NFL this year. But so is basically everyone else.
It’s still relatively early in the NFL season, but signs point to this being one of the worst seasons ever for simulation & statistics based predictors of game results. In fact, having followed several websites for the last few years, this is by far the worst I can remember each one doing as far as accuracy is concerned.
Here, I summarize results through week 7.
Football Outsiders (FO) : These guys have pretty much set the standard for NFL statistical analyses, as demonstrated by their preseason almanacs, appearances across the media, and downloadable spreadsheets with all sorts of good information. In their first five years of picking games against the spread (ATS), from 2008 to 2012, FO finished with yearly success rates of 53.7%, 51.2%, 56.1%, 52.0%, and 57.8%, respectively. There’s no public access for historical picks, but I’ve followed along and these numbers are 100% trustworthy.
This Fall, however…
View original post 606 more words
NFL rankings – October 24, 2013
Updated: October 24, 2013
Pro: The rankings are based on how a team performs and accounts for how many points they would be expected to score based on their statistical output such as rushing yards, passing yards, etc. This ranking considers past seasons statistics with heavier weights placed on games that are more recent. This ranking is the more predictive of the two.
Retro: This ranking only considers strength of schedule and the actual outcome of games in 2013. This is a ranking of who actually has had the best season.
SOS: Is strength of schedule.
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Sports “Journalism”
I really enjoyed the below comment from this Deadspin article:
This sir, is exactly how I feel. I’m a journalism student and my professors hate Bill Simmons. Not because he isn’t a talent journalist, but he hasn’t been a journalist for the last 5 years and yet writes douchebag seriousness on his “Grantland” website that many take as gospel. I like Katie Baker and some of the others on Grantland, but Simmons and O’Reilly just need to get locked in a room by themselves and see who’s ego wins. At least then, we would only have one profound douche in sports media.
Cheers!
Selective endpoints and the using statistics to tell your story
I tweeted earlier today expressing sketicism about an article I read on the Regressing section of Deadspin about west coast football teams travelling to the east coast. I thought that when I had some time tonight, I’d downlaod the data and explore the question myself, but it looks like Mike Lopez (@statsbylopez) beat me to it. And my skepticism may have been warranted.
Cheers.
“There are lies, damned lies, and statistics”-Mark Twain
There was an interesting post at sportsinsights.com earlier today, which looked at the performances of West Coast NFL teams based on game location. The authors hypothesize that “NFL West Coast teams traveling east suffer declines in performance.”
It’s an interesting idea, and, if true, could make the NFL re-think scheduling, which often requires teams to travel thousands of miles on consecutive weekends. Moreover, I liked how the authors looked at team performance against the spread, in contrast to this article at Advanced NFL Stats, which simply looked at team performance, and thus was not able to account for difference’s in the abilities between teams on different coasts.
The topic was interesting enough that it was look at by more than 12,000 viewers (as of 4:52, Friday) when linked by Deadspin.
Further, the results of the Sports Insights study are interesting…
View original post 568 more words

