After we looked at five different statistics to judge offensive players, it’s time to turn the ball over to the defense and focus on the most common defensive statistic: Tackles. From 1994 to 2001 the statistic was consistently kept, but it wasn’t until 2001 that it became official.
A Tackles is a statistic that any defensive player can generate, since it is simply awarded to the player who brings down the ball carrier to end a play. It would seem to make sense that players who do this more often would be thought of as the better defenders because they are preventing the offense from moving forward.
While it’s nice to have a statistic to use for all defensive players and not just pass rushers or defensive backs, there are a lot of reasons why this one shouldn’t be trusted an shouldn't necessarily be used as evidence for a great game. There are better options.
Official Doesn’t Equal Accurate
During an NFL game, a lot of things are recorded after every play. While it isn’t too difficult to see what down it is and which offensive player(s) touched the ball, it’s tougher to determine who made each tackle. Because this is all done in real time, rather than after the game, the player marked down isn’t always the player who made the tackle.
There are typically a few statistical revisions made during the week between games, usually in regards to plays involving sacks and fumbles. Outside of these plays, the NFL doesn’t double check for incorrectly attributed tackles.
Here at Pro Football Focus, all of our analysis is done after the fact from re-watching each play multiple times. We have frequently found situations where the player that was officially credited with a tackle was not the player who actually made the tackle. In fact, we’ve found occasions where the official tackle went to a player who wasn’t even on the field. Stephen Tulloch of the Tennessee Titans, for example, officially finished the season with 111 solo tackles and 49 assists. We found him to have 128 tackles and 34 assists.
In order for tackles to be used to evaluate players, they first need to be accurately recorded by the NFL.
Tackles on Pass Plays
There is a difference between making a tackle on a run play and on a pass play. On pass plays, incompletions and interceptions are clearly to the benefit of the defense. However, if the pass is complete, it often results in a successful play for the offense, and, unless the completed pass produces a touchdown, or the receiver goes out of bounds untouched, a defender is credited with a tackle.
It is typically better for the defender to stop the ball from being completed, but, if they can’t do that, making the tackle is the next best action. In this case, the tackle (generally assumed to be a positive mark) is a bad thing since the primary objective wasn’t achieved and the catch was made. Of course, it is favorable to missing the tackle altogether, but a tackle is not the optimal outcome here.
This makes tackles for cornerbacks the most misleading. Since, generally speaking, most of their tackles come on pass plays, and therefore, after a catch has been made. It also makes it confusing for safeties and linebackers, since tackle statistics aren’t typically kept separate for pass and run plays.
Stops Instead of Tackles
On run plays, the relative value of a tackle is a little more clear cut, but not an entirely better tool for evaluation. When it comes to running the ball, there are some players that offenses like to avoid, and others that they plan to run toward. This results in some weaker run defenders getting more tackle opportunities and some better run defenders getting less.
Even if defenders had equal opportunities to make tackles, not all tackles are good tackles. We discussed this idea for pass plays, but it’s also true for runs. A tackle that results in a loss of yards or no gain is clearly a positive play, and can be credited to the defense. While these are sometimes team efforts, we credit one defender.
On plays where the offense gains a first down, an obvious failure by the defense, someone still gets awarded a tackle. On any play that brings the offense closer to a first down without reaching it, judging it as a failure or success can be difficult. A certain percentage of needed yardage for a first down is typically used to define that line, and that’s what we do at Pro Football Focus. Making a tackle on a “failure play” for the defense is again better than not making a tackle at all, but on traditional stat sheets, this tackle is counted just as any other.
At PFF, we keep track of a statistic that we call “Stops.” A player gets credit for a Stop when he makes a tackle on a “success play” for the defense. While Stops only recognize the “good” tackles, it is still a step above the Tackles statistic, which includes all tackles regardless of where they occur.
Tackles gives us something that no other number does, a statistic that applies to all defensive players. However, like any stat, it is essential to put the numbers into context, and in this case it’s even more necessary. Te begin adding that context, tackles need to be broken up into pass and run plays, and positive and negative plays.
Until the media uses tackles more intelligently – like incorporating Stops into their reporting – people will keep thinking that racking up a lot of tackles automatically equates to a great game, while in actuality, that may not be the case.