tag:blogger.com,1999:blog-5204092591876211047.post6179014824778751202..comments2016-07-29T03:02:20.310-04:00Comments on Advanced NFL Stats Community: NFL Coach Quality: A Bayesian Approach To Approximating the Value of Coaches - UPDATEDUnknownnoreply@blogger.comBlogger11125tag:blogger.com,1999:blog-5204092591876211047.post-953235174799783742012-01-16T13:22:49.736-05:002012-01-16T13:22:49.736-05:00And what is BUGS?? I think you need to explain wh...And what is BUGS?? I think you need to explain what you are doing better.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-18536072881167568172012-01-16T13:19:27.810-05:002012-01-16T13:19:27.810-05:00Probably need to explain hoe bayesian analysis wor...Probably need to explain hoe bayesian analysis works....and whatever the microsoft algorithm you used to normalize.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-51579940934469914162012-01-15T10:53:31.032-05:002012-01-15T10:53:31.032-05:00I'll point out that the Bayesian results are 0...I'll point out that the Bayesian results are 0.946 correlated with simply dividing wins by 16. So for most purposes, the straight-up winning percentage is probably sufficient.<br /><br />One potential point of interest, is can you form any hypothesis as to what the remaining variation is due to? (By looking at which coaches over and underperform in the Bayesian value relative to the straight-up value, and trying to think about similarities in each set.)<br /><br />If one is being careful, there is no need for the "season standard deviation". The draw should not be from a normal distribution with an unknown mean winning percentage and standard deviation, it should be from a binomial distribution with an unknown winning percentage. The variance of a binomial distribution is given by its mean, and so the extra parameter is unnecessary.<br /><br />In fact, from a binomial perspective, it is impossible to get a "season standard deviation" (taking the square root of the variance) that is above 2. The fact that you found a value above 2 is probably the most interesting result of the analysis. It means there is some unknown additional factor (time-series non-invariance being the most likely culprit).Andrew Folandhttp://nuclearmangos.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-60692922521856126092012-01-12T13:07:19.642-05:002012-01-12T13:07:19.642-05:00I hope that version 2 of the article answers some ...I hope that version 2 of the article answers some of the comments above, both in terms of the math and the goals of this piece.David Durschlaghttps://www.blogger.com/profile/16575803679513893558noreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-15619567500026751692012-01-08T03:03:24.412-05:002012-01-08T03:03:24.412-05:00Yes, assuming that a head coach is mostly responsi...Yes, assuming that a head coach is mostly responsible for drafting/trading/signing is a very poor assumption. Without this assumption the entire article becomes misleading at best.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-1337393290330761612012-01-07T09:14:24.581-05:002012-01-07T09:14:24.581-05:00Yes the Chargers had many pro bowlers which Turner...Yes the Chargers had many pro bowlers which Turner inherited from Schott (another timid coach, who not coincidentally never won a playoff game, but at least his teams were ready by september). After all, as you said, Turner "had nothing to do with that". All he did was wasting the most talented team of the late 2000´s. <br /><br />No, Beli-Cheat, as we readers all know, is a great coach (from a pure football standpoint). Year in year out he has more wins than expected by Brians and others great models. <br /><br />But as i said before, i still appreciate your good work.<br /><br />Karl, GermanyAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-9597005375996313162012-01-07T09:08:58.638-05:002012-01-07T09:08:58.638-05:00Boston Chris -- you are correct. This is largely b...Boston Chris -- you are correct. This is largely based on which teams won the most. The idea is to attribute those wins to their head coach, since he has final say over the teams. I'll write more about how much information this adds (i.e. how strong predictions based on these rankings are) some point soon. The fact, however, that the model does not measure the things that cause a team to win does not mean it cannot predict which teams (i.e. coaches) will win in the future.<br /><br />As to Tony Dungy himself -- one could argue as to whether the model applies well to him. To be honest, I think it does. His continuous success on both the Buccs and the Colts may have had extenuating circumstances, but all success involves a bit of luck. That he did it so consistently for so many years indicates that, given the opportunity, he'd probably do it again -- and that is what I set out to measure.David Durschlaghttps://www.blogger.com/profile/16575803679513893558noreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-15746753839115877232012-01-07T09:01:08.773-05:002012-01-07T09:01:08.773-05:00I'll address the first response later, as it r...I'll address the first response later, as it requires a somewhat more complex explanation, but the second is simple -- it's a matter of assumptions. The model assumes the difference between a coach's win count for a season and their actual skill or value can be modeled by Gaussian noise. If you believe the majority of Turner's career took place starting from a dominant team with a brilliant GM, which he gradually destroyed, well, that's not Gaussian noise. In other words, it's the same argument as "Belichick is only the top coach because he got lucky on Tom Brady" -- it may be true, but the model doesn't incorporate that information.<br /><br />Also note that this is an attempt to evaluate a head coach in a way that considers team composition as part of a head coach's responsibility (which it is -- free agency, the draft, and trades are usually controlled by a team's head coach). I suspect the FO study was an attempt to measure coach value independent of player value -- what a coach actually does in terms of clock management, play design, etc. to take the same group of guys and make them better or worse.<br /><br />To summarize -- the charges had a lot of pro bowlers under Norv. If you think he had nothing to do with that, then you will disagree with his ranking in the model. You may be right -- it is, after all, just a model.David Durschlaghttps://www.blogger.com/profile/16575803679513893558noreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-14329722597540533132012-01-07T08:56:49.034-05:002012-01-07T08:56:49.034-05:00Tony Dungy and his ultra-conservatism #2? I think...Tony Dungy and his ultra-conservatism #2? I think what this ended up measuring is which teams won the most. Although I really appreciate the effort.Boston Chrisnoreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-85342333505780588602012-01-07T07:54:53.725-05:002012-01-07T07:54:53.725-05:00How comes Norv Turner is 28th out of 107 ??? AFIR,...How comes Norv Turner is 28th out of 107 ??? AFIR, the guys from FO did some work before the 2008 season; there he is the worst coach in the history of the NFL (rightfully chosen, b/c even w/o numbers the human eye can witness this every given sunday :-)). He lost the most games when entering the 4th Qtr and he had the fewest 4th Qtr comebacks. I doubt he improved in the last few years, b/c he is the same timid coach he always was. And we shall remember he inherited a 14-2 team which could have won some superbowls (i totally agree with Ryan here). Otherwise, i appreciate you work.<br /><br />Karl, GermanyAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-5204092591876211047.post-14698286290358396522012-01-06T22:12:00.691-05:002012-01-06T22:12:00.691-05:00How is this a measure of coaching value? It's...How is this a measure of coaching value? It's a (crude) measure of the quality of teams a given coach has had. The main assumption you are making is that all teams have the same skill level -- clearly false. If you want to attempt to measure the value of a coach, you have to do some kind of analysis of how the team performed just before and just after his tenure. Even that would be pretty severely biased by unaccounted-for personnel changes.Anonymousnoreply@blogger.com