tag:blogger.com,1999:blog-38600807.post6510707214732268034..comments2023-11-05T04:16:44.937-05:00Comments on Advanced Football Analytics (formerly Advanced NFL Stats): Improving Statistical Analysis in the NFLUnknownnoreply@blogger.comBlogger21125tag:blogger.com,1999:blog-38600807.post-33055028132456082012011-04-07T21:27:10.454-04:002011-04-07T21:27:10.454-04:00So I suppose median concentrating around 3 yards o...So I suppose median concentrating around 3 yards or so relates to how runs typically formed, being either stuffed or stopped by the defensive line or running back. If I had to make wild speculation, median would favor the running backs that have tendencies to "fall forward," who can stumble an extra yard after solid contact. <br /><br />And perhaps my fear of averages is being burned so many years in a row by fantasy football, the chance that any particular run play may result in significant yardage.FourthandFortyTwohttp://fourthandfortytwo.blogspot.com/noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-91429029609697814232011-04-07T02:14:20.284-04:002011-04-07T02:14:20.284-04:00One thing that could add value is football compute...One thing that could add value is football computer simulation. An extremely crude version might be an internet game like http://goallineblitz.com/<br /><br />If you actually tried to build a more serious model you could illuminate a lot of strategies and get an idea of how a player can fit into a system. You could use a mix of statistics and scouting to try and model a players behavior and then run the simulation over and over.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-15786817641654366352011-04-06T14:44:32.627-04:002011-04-06T14:44:32.627-04:00Great post.
If I had to choose one change, I thin...Great post.<br /><br />If I had to choose one change, I think I would choose more accurate accounting of who was on the field (although the conversion of yards to feet is very tempting). I'm surprised, in fact, that it's not the norm, as it's not an extraordinarily hard task. All numbers are registered, and to make things easier, they even put names on the jerseys. Most production shots do not capture all of the jersey names and numbers, but the coaching film that the NFL has exclusive rights to almost certainly does.KernelReeferhttps://www.blogger.com/profile/14284097281238034150noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-44517923553058367372011-04-06T00:24:06.674-04:002011-04-06T00:24:06.674-04:00I'm not exactly sure where this should be post...I'm not exactly sure where this should be posted, so I just opted for the most recent entry.<br /><br />I was wondering what your thoughts are on the kickoff being moved up to the 35. Specifically, how much more valuable will it make a surprise onside kick?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-16167061837448295682011-04-05T23:36:28.408-04:002011-04-05T23:36:28.408-04:002000-2010 rushing stats (runs by non-QBs in 1st an...2000-2010 rushing stats (runs by non-QBs in 1st and 3rd quarters occuring between 10 and 80 yards from own goal line):<br /><br />median: 3 yards<br />mode: 2 yards (13.4% of all runs)<br />average: 4.43 ypc<br /><br />The distribution is positively skewed, which is why the median and average are higher than the mode.<br /><br />All the measures of central tendency are biased in some way when attempting to measure rushing productivity. Average tends to favor high-variance rushers while median tends to favor low-variance rushers. Both types of players can be very good or very bad, which is why I think it is important to look at a variety of metrics and not fall in love with one. But if you're more interested in median yardage, you can get a good idea of how a certain player or team performs in that category by looking at success rate.Brettnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-6460619542165948252011-04-05T17:09:46.488-04:002011-04-05T17:09:46.488-04:00Fourth and Fourty Two, the way stats are currently...Fourth and Fourty Two, the way stats are currently constructed yards gained and lost are only whole yards. As the vast majority of running plays result in 3 yard gains, every single runningback with enough carries to matter would have a 3 yard median, making that stat totally useless. If we could break yards down to feet, tenths of a yard, etc, that would be more useful, but as it stands now median would not be any more helpful.Jameshttps://www.blogger.com/profile/01838293735141324662noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-71093708033537745282011-04-04T14:20:18.686-04:002011-04-04T14:20:18.686-04:00and by assed i mean assesed.and by assed i mean assesed.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-37564517861160252312011-04-04T14:19:02.109-04:002011-04-04T14:19:02.109-04:00One of the biggest issues with quantitative analys...One of the biggest issues with quantitative analysis in football, basketball, and other major sports that are not baseball is the fact that the increase in certain statistics for one player can often negatively correlate with the same stats for his teammates. It's easy to see in basketball - only one player can grab a rebound after a missed field goal; only one player can score on a possession. In football, only one player can bring the ball into the endzone. Every rebound that your teammate grabs is a rebound that you cannot get. Rate statistics and efficiency statistics can remedy only some and sometimes none of the problem.<br /><br />Baseball is very different. Your teammates can't "steal" homeruns from you. Even if we could measure the true contributions of a basketball or football player in a given game or season, we cannot measure what their contributions may have been with different supporting casts. Stats like adjusted +/- try to get at this, but are far from perfect.<br /><br />Also, I think it's important to refrain from assessing the validity of statistical analysis as a whole. Yes, it's true that quantiative analysis in its present state has limitations and should be used in tandem with old-school methods like scouting. But this does not mean all stats are on the same level. From some numbers, we can dervie a great deal of information - "scouting" may be almost unnecessary. In other cases, the numbers don't even begin to tell half of the story. Each metric needs to be assed on its own scale.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-7092963080845008282011-04-03T10:10:10.272-04:002011-04-03T10:10:10.272-04:00I don't think the NFL would go with medians. I...I don't think the NFL would go with medians. In terms of run plays over the course of the year that could be a useful number, but when a rusher only has 9 rushes in a game, the median yards for that game wouldn't be meaningful. When it comes to passing, if a QB completes less than half his passes, the median would be 0. Also it would make a lot of running backs look equal, since everyone will be within a few yards of the same, and so many people tied since there wouldn't be decimals.Nathan Jahnkehttp://www.profootballfocus.comnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-85718933908933987502011-04-02T15:12:17.847-04:002011-04-02T15:12:17.847-04:00Well, one thing I would like to move away from is ...Well, one thing I would like to move away from is the whole "Yards Per" idea (average yards per play) and instead embrace median yards per play. Think about it this way, what is more valuable to a team: a "home run" style running back who averages 4-yards per carry, but barely gets more than a yard on a single play; or a running back who's guaranteed to get 4 yards every play?<br /><br />I think we just all default to the idea of averages because they are easy to wrap our minds around, but I find it hard to think of football as a game of averages.FourthandFortyTwohttp://fourthandfortytwo.blogspot.com/noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-86685606274450103792011-04-01T11:10:46.931-04:002011-04-01T11:10:46.931-04:00Isn't EPA essentially a form of +/- for yards?...Isn't EPA essentially a form of +/- for yards?Jameshttps://www.blogger.com/profile/01838293735141324662noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-41369744507745450652011-03-31T22:12:26.871-04:002011-03-31T22:12:26.871-04:00Correction: There are not 512 games in the NFL re...Correction: There are not 512 games in the NFL regular season, there are 256.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-10917595569192951012011-03-31T20:58:07.107-04:002011-03-31T20:58:07.107-04:00Great suggestions, great examples, and surprising ...Great suggestions, great examples, and surprising depth. Great work.Jacob Stevenshttps://www.blogger.com/profile/16635038007666752332noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-71037400685368928142011-03-31T17:03:14.955-04:002011-03-31T17:03:14.955-04:00If one *could* apply +/- to football, I think I wo...If one *could* apply +/- to football, I think I would like 1st downs to be the measurement of choice. Sure, with small sample size, certain players could be "overrated" or "underrated", just like any stat. But the reason I say first downs is this: If you're the 3rd down slot receiver, your job is to help the team get that 1st down. If you (or a teammate) gets that 11 yd. catch on 3rd & 10, then that's good. If you got 9+, but ultimately punted, then that's bad. Sure, there will be a couple of 3rd & 10 from the opponent's 40 that become 4th & 1 from the "31" that leads to a FG, which should be counted as a partial success--the ball was moved into FG range vs. punting from the 40. <br />By the same token, shouldn't a 50+ yd TD be counted extra because there could have been multiple opportunities for the drive to fall short of points? These and other similar conundrums lead me to believe that plus-minus would be difficult/impossible to implement--for one, all scoring plays do not have the same value. <br /><br />On the other hand, I do agree with the spirit of John's post: football stats could be better. And although statisticians have their "favorite" stats (EPA/WPA, DVOA/DYAR, etc.), my opinion is that any team/owner willing to outlay some cash to hire 2 or 3 guys to just go over film [esp. all "offseason"] and look at things discussed in sites like this one would benefit in a major way.Josephnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-18837629060209516572011-03-31T14:58:41.091-04:002011-03-31T14:58:41.091-04:00A good number of wise people in different fields h...A good number of wise people in different fields have noted that statistical/quantitive analysis better informs judgement, but does not replace it (and should not). We still come down to having to reach opinions. The better the objective, empirical information we base them on, the better they should be -- but we still come down to that.<br /><br />Moreover, NFL football is forever cursed for quantitative analysis purposes by the problem of small sample size. Much more so than any other major sport. There is just no way around that. (*If only* NFL teams played 162 games a year and had an historical data base of 300,000 games played with only minor rules changes!)<br /><br />The "plus minus" idea is an example of that. I'm not an expert on plus-minus or the NBA, but have seen discussions among those who are indicating that while *in theory* it is a great way to evaluate NBA players, in practice to be applied with confidence it needs a sample size of maybe about 200 games, when there are "only" 82 in season. So to apply it during a single season inevitably requires the proverbial finger lightly tapping the scale to move the result in the "more credible" direction.<br /><br />Be that as it may, and I'm no expert on that dispute, that's for NBA basketball which is a far simpler game than football, with only 10 players on the court and a big, fat 82-game season. I don't see how plus-minus could ever be applied in the NFL except in very limited, specialized situations. Way too small sample size. And alas it's the same for many other potentially good analytical ideas.Jim Glassnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-31903676759715359632011-03-31T13:52:36.411-04:002011-03-31T13:52:36.411-04:00I'm so glad you mentioned scouting. Even if th...I'm so glad you mentioned scouting. Even if the resolution of distance improved dramatically, there's still so much information that is lost in the way stats are recorded. More and more people are applying more and more advanced analytics to numbers that, as you point out, are pretty-rough-and-ready to begin with. Worse, others are treating the precise-to-the-Nth-decimal results as unassailably "objective," even though a whole bunch of subjective human judgment goes into both the creation and analysis.<br /><br />Peace<br />TyTy Schalterhttps://www.blogger.com/profile/07228238666916939672noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-89036636098359348052011-03-31T10:30:04.078-04:002011-03-31T10:30:04.078-04:00Football still insists on using volume stats (e.g....Football still insists on using volume stats (e.g. total yards, total points scored) instead of averages. <br /><br />I'd be thrilled to see announcers and analysts start focusing of measures like QBs YPA and a RB YPC instead of 300 yrd and 100 yrd games. <br /><br />and yes, would love to improvement in game logs as well.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-78321010495819073512011-03-31T02:51:57.057-04:002011-03-31T02:51:57.057-04:00At what point do they just put chips in each playe...At what point do they just put chips in each player's helmet, kind of a low-res motion capture? Then the data could be played back and we'd always know exactly where each player is on the field. <br /><br />The ball should have a chip too that understands orientation - it'd know when it crossed the goal-line, how many orientations it has in a throw, etc.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-43680278245550089012011-03-30T22:22:52.533-04:002011-03-30T22:22:52.533-04:00A plus/minus in terms of scoring may not be useful...A plus/minus in terms of scoring may not be useful, but plus/minus in terms of yardage (or whatever measurement we end up with) could be informative.Brian Pnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-88621062942490710792011-03-30T21:10:15.679-04:002011-03-30T21:10:15.679-04:00Speaking as someone familiar with plus/minus, both...Speaking as someone familiar with plus/minus, both in hockey and basketball, it will take a minor to medium-sized miracle for the technique to work in football. The lack of variability in the players on the field on any given play will make it impossible to tell anyone apart. Although I would be pleasantly surprised if it worked.Alexhttp://sportskeptic.wordpress.comnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-80335445027789209862011-03-30T20:55:18.051-04:002011-03-30T20:55:18.051-04:00As a European, "feet" is still a very in...As a European, "feet" is still a very inaccurate (and weird) measurement to me.<br /><br />But yeah, I couldn't agree more with the post. Of course, even with all changes implemented the statistician's job becomes easier but still imperfect for the sport. Limitations are limitations no matter how you look at it.<br /><br />I doubt the NFL has much interest in improving the available statistics, sadly. Which in a way is "amusing" because of the prevalence of statistical triggers in player's contracts. You'd think with that habit they'd like some more meaningful measurements.Vasiliinoreply@blogger.com