tag:blogger.com,1999:blog-38600807.post666898669102008507..comments2023-11-05T04:16:44.937-05:00Comments on Advanced Football Analytics (formerly Advanced NFL Stats): "Tackle Factor"Unknownnoreply@blogger.comBlogger31125tag:blogger.com,1999:blog-38600807.post-83243919031502742872013-01-03T07:27:09.239-05:002013-01-03T07:27:09.239-05:00Bear in mind that this is hugely affected by the D...Bear in mind that this is hugely affected by the Defensive Line. If you have a monster inside DL, teams are not going to be ploughing up the middle at you, is that going to make your ILB or MLB look weak? and vice versa. I like the idea but I'm not sure it can be so easily broken down into a single value, much like a similar pass defence factor for DBs since teams actively throw away from premium defenders. It's all a bit hard to decoupleDrManhattan71https://www.blogger.com/profile/03097872106155390972noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-33825639646813018002012-12-05T11:24:46.768-05:002012-12-05T11:24:46.768-05:00Great article, but the percentage table doesn'...Great article, but the percentage table doesn't seem to add up? For a 3-4 defence it totals 94.0% for a 4-3 it totals 95.10% - why is it not 100%? (Special teams tackles included, perhaps?)<br />Anonymoushttps://www.blogger.com/profile/16235963958996089084noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-52255559758294540392012-10-28T01:07:14.314-04:002012-10-28T01:07:14.314-04:00What about a stat for tackle efficiency? Like cont...What about a stat for tackle efficiency? Like contact rate in baseball, shouldn't there be a stat showing how effective a player is at tackling? <br /><br />I remember reading an article about defensive backs on the issue a few years ago. Basically, it said that while many defensive backs might look like stars on the surface because of great INT stats and tackle totals, they might actually be underperformers (and vice verce for underrated guys). They used a stat like tackle success rate, and found that Jim Leonhard was one of the NFL's most sure tacklers, yet got very little credit as a solid player, while Antonio Cromartie-- lauded as an elite corner-- whiffed on many of his attempted take-downs. <br />Ryan S. Kelleyhttps://www.blogger.com/profile/03936377772040535800noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-72623547680664262672010-05-13T21:59:26.044-04:002010-05-13T21:59:26.044-04:00Strong work, Brian. Just caught a link to this po...Strong work, Brian. Just caught a link to this post today.<br /><br />You'll want to strongly consider using some form of stadium factor in your next iteration of these stats. <br /><br />Despite the good work that the NFL's statistical coordinator has done since 2007 in trying to bring uniformity to the solo and assisted tackle statistic, there are still very significant differences in how each stadium's stat crew tallies solos and assists. <br /><br />Some crews (eg STL, ATL, JAX) are extremely stingy with assisted tackles. Others (eg NE, CIN, CLE) will give them out in bunches, often choosing to give two assisted tackles instead of one solo and one assisted.<br /><br />We've been tracking percentage of team solo tackles and tackle opportunity at FBG for some time now and would really love to see better tracking of tackle numbers so that metrics like what you've attempted here can be all that they could be.<br /><br />And getting reliable snap data to allow per snap metrics would also lots of improvement to defensive stats.<br /><br />We may never be able to fully drill down through the team nature of defensive football to get metrics that don't have to be considered with a healthy dose of context, but here's hoping efforts like yours will continue to get us closer to that goal.Jene Bramelhttp://footballguys.comnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-30459572564396013392010-05-12T22:44:41.407-04:002010-05-12T22:44:41.407-04:00Hey Brian, as usual an interesting read.
Just wan...Hey Brian, as usual an interesting read.<br /><br />Just wanted to add that sacks and forced fumbles are (last I checked) not counted as tackles. I think it makes sense to include these in any "basic" version of this stat, and not just in a special weighted expanded version. Both, like tackles, involve stopping offensive action and should be counted accordingly. After all, does it make sense to penalize a 100-T 10-S 5-FF MLB who stops exactly as many plays as a 115-T 0-S 0-FF MLB?<br /><br />(Unfortunately strip-sacks are recorded as both a sack and a FF, so adding up T+S+FF will double-count these stops... but in the absence of play-by-play data, this discrepancy should be pretty small.)<br /><br />I suppose, if you're using full tackle data and not just run plays only, the same argument can be made to also include INTs and PDs. PDs in particular are unfortunate since they seem to be assigned arbitrarily, but I think it does still add to the picture.<br /><br />Hmmm, I guess offensive penalties forced would also then meet that bar. Those I think you can safely ignore without play-by-play data -- they number < 10 per team a game, of which only 1/3 - 1/2 are offensive, of which only a fraction are forced. ~50 "stops" a season by penalty per team isn't insignificant, but won't affect many players' numbers.<br /><br />What do you think?<br /><br /><br />One note on TF by snap: not all snaps are created equal, as I expect the tackles-by-position distribution to vary in say dime packages vs goal-line defense. A part-time player thus won't be measured fairly even going by snap if he's primarily a sub-package player. For that matter, if a part-time player is a 1st/2nd-down or a 3rd-down only player, I'd suspect the tackle distribution to vary quite a bit there too. However, I'd guess a snap-adjusted TF probably does work for older or rotation players who split snaps non-situationally (e.g. by series).Michael Lnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-81489056697823319802010-03-18T16:32:15.537-04:002010-03-18T16:32:15.537-04:00Not in the data I have, unfortunately. The only pl...Not in the data I have, unfortunately. The only place I've found # snaps publicly available is at a website called profootballfocus.com. But I'm not sure how reliable their numbers are. Ultimately, that's my intent with TF-->make it a per snap stat.Brian Burkehttps://www.blogger.com/profile/12371470711365236987noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-75683259021248092892010-03-18T15:59:42.708-04:002010-03-18T15:59:42.708-04:00Brian,
Thank you for responding.
It would be inte...Brian,<br />Thank you for responding.<br /><br />It would be interesting to compare "full time (every down)" players.<br />Is there any way to get a "# of downs played percentatge"?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-23334532178005128342010-03-17T17:47:05.242-04:002010-03-17T17:47:05.242-04:00Oh, also regarding Dansby... 1.01 turns out to be ...Oh, also regarding Dansby... 1.01 turns out to be solidly above average (as it's now formulated). Most guys do not play every down, and the numbers above do not filter out special teams tackles (or offense tackles following turnovers) yet. Right now I've got him at 27th in TF out of 134 LBs who played in 6 or more games.Brian Burkehttps://www.blogger.com/profile/12371470711365236987noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-18791757134221607182010-03-17T17:32:48.134-04:002010-03-17T17:32:48.134-04:00Yes. Other players can 'steal' tackles fro...Yes. Other players can 'steal' tackles from another guy, say a really good DT can eat some tackles that would otherwise go to the LB and vice versa. <br /><br />They have the same problem in baseball, where one fielder with a lot of range eats up the put outs that would typically go to an adjacent fielder. They have adjustment systems for this, but I'm not an expert on them. They also have ways of adjusting for park factors (that thankfully we don't have to worry about in football.)Brian Burkehttps://www.blogger.com/profile/12371470711365236987noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-87322588322373457812010-03-17T16:47:47.336-04:002010-03-17T16:47:47.336-04:00Brian,
Might not a player playing on a good defens...Brian,<br />Might not a player playing on a good defensive team get "cheated" of some tackles as his team mates "steal" his tackles. Likewise, playing on a poor defensive team, a player may get to make tackles his team mates couldn't make.<br /><br />What impact does playing on a good/bad defense have on the Tackle Factor, and might you be able to account for this? Like a scaling factor based on the quality of the rest of the defenders around you.<br /><br />Also - if Dansby has just a 1.01 Tack Factor, doesn't that imply that Bill Parcells over paid? Or maybe Parcells sees something he likes, and doesn't value TF highly.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-21731027830758783942010-03-09T05:49:33.677-05:002010-03-09T05:49:33.677-05:00I love this stat!I love this stat!Samponoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-73328069535450087742010-03-06T13:46:32.133-05:002010-03-06T13:46:32.133-05:00I agree with Jim Glass above that analysing footba...I agree with Jim Glass above that analysing football is incredibly more challenging than baseball, because of all the range of interaction between all players.<br /><br />It is in my opinion a mistake to use statistical analysis for purposes of evaluation of individual players, both in defence or in offence. Credit of a play cannot be attributed to one single player (a QB or a RB, typically), not even easily distributed among players.<br /><br />Concerning Tackle stats, I think they must at some point be associated with the number of yards allowed in the given play.Ludwighttp://www.facebook.com/?ref=home#!/profile.php?ref=profile&id=578868371noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-23368981704021684452010-03-05T21:19:17.754-05:002010-03-05T21:19:17.754-05:00I think you're on to something and this defini...I think you're on to something and this definitely has some value, although I think it has less value than it does in baseball. In baseball, the distribution of fielding opportunities is almost random. You can argue that a strong pitcher will give his infield more fielding opportunities (on ground balls) and a poor pitcher will give his outfield more fielding opportunities (on fly balls), but other than that, the actual position receiving the fielding opportunity is so random.<br /><br />This is quite different on a football field. In rare cases, a defensive line can be so strong as to take tackling opportunities away from the defenders behind them. More frequently, I see defensive lines and linebacker corps that are so WEAK that they actually give more tackling opportunities to the secondary. This effect is particularly acute in run defense. There can also be secondaries that are so strong that they give tackling opportunities to the DLs and LBs (because the opposing offense is reluctant to throw against them).bytebodgerhttps://www.blogger.com/profile/15989876051555196561noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-68532169763469966312010-03-05T19:14:26.666-05:002010-03-05T19:14:26.666-05:00Defensive stats can be perverse.
As James has po...Defensive stats can be perverse. <br /><br />As James has pointed out (since he's been mentioned) superior counts of good plays can actually indicate bad play -- for instance, a league-top number of double plays generally indicates poor infield players rather than good ones, because poor infields have more runners on base; first basemen with superior assist numbers generally are immobile fielders who can't catch the ball and get over to the base themselves so they have to lob to the pitcher, etc. (a couple of James' examples).<br /><br />And baseball is the simplest sport to analyze because its stats record individual actions that occur in sequence, the number of plays is limited and consistent, and defenses are pretty uniform.<br /><br />Football has 11 (really 22) players all interacting simultaneously, applies different systems of offense and defense that affect players' numbers, etc., and so is a <em>whole lot</em> more complex to analyze by D numbers.<br /><br />This is not a criticism of TF. It's just saying that analyzing D stats will be a challenge. Good luck!Jim Glasshttp://www.scrivener.netnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-32755112489904184812010-03-05T18:52:10.031-05:002010-03-05T18:52:10.031-05:00Does this number adjust for pass/run ratio? For ex...Does this number adjust for pass/run ratio? For example: A DE has a lot more tackles on run plays than pass plays. You have to adjust because some teams face a lot more run plays than pass plays and vice versa.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-24929502542898077762010-03-05T14:21:45.592-05:002010-03-05T14:21:45.592-05:001. every single tackle is better than no tackle, n...1. every single tackle is better than no tackle, no matter where or how it happens.<br /><br />An incomplete pass or pass not attempted is better than a tackle after a completed pass. A tackle from one player that comes after that players has abandoned his assignment is also not as valuable as a tackle not recorded from one player, but recorded by another because the first player did his job.<br /><br />2. Every single tackle is the very first tackle a defense can make,<br /><br />Only within the definition of the play as it happened. If the person who ultimately made the tackle did something else, like contain the backside, the tackle could have been accomplished earlier.<br /><br />Seattle had a player named David Hawthorne who would record a ton of tackles, and he did because he was poor in coverage, took long angles to the ball carrier, and was not assignment correct. He recorded tackles, but his tackles came at the expense of better outcomes.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-43992166038623569042010-03-05T12:40:36.051-05:002010-03-05T12:40:36.051-05:00I think I'm a little more concern with the dis...I think I'm a little more concern with the distortion of an above average player on a below average defense. I don't watch baseball at all, but my understanding is that this stat wouldn't be influenced by the rest of the team, right?<br /><br />SF was ranked #10 in your metric last year, so Willis probably isn't getting any particular help there, but imagine what his TF would be on Cle, StL, or Det?<br /><br />I don't know any way to control for that, other than to say "Player X has a TF of Y on a Z ranked Defense." That logic makes Foote look pretty bad.<br /><br />I wonder what the TF distribution looks like for bad teams as opposed to good ones? Do safety and FS have higher TFs? Is there an ideal, instead of league average, TF distribution among the good teams?Dr Obvioushttps://www.blogger.com/profile/00966038406811006557noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-78689215400173019002010-03-04T18:14:26.767-05:002010-03-04T18:14:26.767-05:00Seeing Jason Taylor so low, I wondered what would ...Seeing Jason Taylor so low, I wondered what would happen if you counted a sack as two or three tackles.Zachnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-18841173290850170512010-03-04T17:40:27.160-05:002010-03-04T17:40:27.160-05:00I'm not sure a standard deviation wouldn't...I'm not sure a standard deviation wouldn't be a good thing to know, just for some relativity on the numbers. Of course, 12% is always going to be better than 10%, but how much better is that extra 2% (for each position).<br /><br />I think this is a great way to start some better analysis on defensive players besides absolute numbers (like, 80 tackles, because, like you said, depending on the situation that could be a good or bad thing).<br /><br />Is the "Interception Factor" coming next?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-83313544481324757362010-03-04T14:22:44.878-05:002010-03-04T14:22:44.878-05:00An out is not always an out. There are fielder'...An out is not always an out. There are fielder's choices, getting the lead runner or trail runner, catching laser line drives or a soft pop up in foul territory. Each play is equal in the eyes of range factor. It seems tackle factor is no more flawed.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-90542852830488432882010-03-04T14:12:13.783-05:002010-03-04T14:12:13.783-05:00True, not all tackles are equal. However,
1. ever...True, not all tackles are equal. However, <br />1. <i>every single tackle is better than no tackle</i>, no matter where or how it happens. And,<br />2. <i>Every single tackle is the very first tackle a defense can make</i>, or else the play would have already been over.Brian Burkehttps://www.blogger.com/profile/12371470711365236987noreply@blogger.comtag:blogger.com,1999:blog-38600807.post-13455362625862063582010-03-04T13:56:43.631-05:002010-03-04T13:56:43.631-05:00Unfortunately, an out is an out, but a tackle is n...Unfortunately, an out is an out, but a tackle is not a tackle, and range is a very limited portrait of a player. A good linebacker might work in unison with his teammates and instead of bowing out and attempting a tackle, instead penetrate and string the run wide, or engage the lead blocker and allow another player to tackle. And I think that's just the tip of the iceberg of potential critiques. Interesting, but I doubt it will tell us much about a player's actual ability.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-71669537877071801152010-03-04T12:20:34.088-05:002010-03-04T12:20:34.088-05:00Brian,
Great work, as usual. Two things:
Do you ...Brian,<br />Great work, as usual. Two things: <br />Do you know what constitutes a tackle when it comes to forcing a ball carrier out of bounds? Does it depend on the amount of pressure (i.e, a nudge vs. a shove)?<br /><br />Also, I can see how this stat could be misleading, for the same reason you can't just look at INTs and passes defended for CBs. If you're a dominant outside linebacker, the opponent's running game plan might be to constantly attack the opposite side of the field, severely limiting that player's tackle %, but not necessarily his impact on the game. Not sure if there'd be any way to split up strong vs. weak side or left vs. right using your play-by-play data, but it might help. Nevertheless, it's a great idea.Ryannoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-1230913381600441152010-03-04T09:54:59.963-05:002010-03-04T09:54:59.963-05:00You've got to be careful with the original dat...You've got to be careful with the original data though. I read something a few years ago about how poorly stats were kept in the NFL and as an example it pointed out that the Colts defense had more solo tackles than they had plays.DMnoreply@blogger.comtag:blogger.com,1999:blog-38600807.post-36292862188128723302010-03-04T09:49:15.794-05:002010-03-04T09:49:15.794-05:00Will-That's due to tackles on special teams an...Will-That's due to tackles on special teams and offensive turnovers. At this point, I'm not sure which tackles are which, so I have accept the discrepancy for now. (The data is not from the play-by-play yet, but from nfl.com defensive player stats.) When I do implement TF using p-b-p data, it will take care of the discrepancy.Brian Burkehttps://www.blogger.com/profile/12371470711365236987noreply@blogger.com