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Toward A Revised Draft Theory, Version 4.0


This was originally posted at DGDB&D about a year two years three years ago, and it was posted here each of the last two years.. I have updated and tweaked it (again) for re-posting here. In addition to adjusting some of the stuff on trading up (based on discussions following last year's post), I've also added thoughts on trading down within the context of the revised theory. I've also tried to give more examples using real players rather than just presenting the theory with variables.

As always, additions and corrections are welcome in the comments. --MDC

Classic Definitions of "Reach." There exists a general consensus when discussing the draft that teams must avoid "reaching" for a player. Loosely, I think we can define "reach" in this classic sense as

Selection of X before pick Y1, where Y1 is the upper limit of a player’s likely draft range assigned by ranking all available players against one another. (i.e. The player "should" go between picks 15-25, thus a pick above 15 is a classic reach.)

It is this classic definition that allows sportswriters and reasonable facsimiles thereof to immediately opine that Jake Locker was a reach last year, while Cam Jordan was a steal.

Obviously, I suppose, within this traditional framework, there is some gray area — there are varying degrees of "reach," such that the team taking our hypothetical 15-25 player at 14 is not near as "incorrect" in their selection as the team taking him at, say, 8.

Implicit in this classic definition of reach is the definition of a "good" pick, defined as:

Selection of X between picks Y1 and Y2, where Y1 and Y2 are the top/bottom limits of the player’s likely draft range, with a selection made after Y2 defined as a "value" pick.

Problems with the Classic Definition. On its face, the classic equation seems valid enough. Given enough rankings, one could conceivably compile them and arrive at an upper and lower limit for each player. The problem lies in the underlying determination of a player’s value. More specifically, the theory assumes some sort of fixed value for each player that allows them to be ranked in a meaningful way; it assumes that the ranking accounts for all (or nearly all) of the variables so that one can accurately compare players of two different positions, from two different teams, who played under myriad different conditions, and come up with a determination of which player is "better."

Such an assumption is inherently false — it has to be — because the data required to accurately compare two players makes your model too narrow to compare many others. This phenomenon is not unique to football, however.

Warning: Strained Analogy Ahead!

There is a theory in particle physics known as the Heisenberg Uncertainty Principle, which states that certain physical properties (position and momentum) of a given particle cannot both have precise measurements at the same time — the more specific you get with one of the measurements, the more general you must be with the other, because defining one necessarily excludes, limits, or ignores the other. While not perfectly analogous, I think you can apply a similar idea to the ranking or relative draft value of players — the more you try to pin down exactly where a player should be drafted in relation to other players, the fewer players you can actually rank (and vice versa: the more players you try to rank, the less accurate you can be with their specific relative values). This is due to the overwhelming number of variables that you have to consider if you want to arrive at your best specific comparison.

Here’s what I mean: I can tell you with a fair amount of certainty that Morris Claiborne is a better cornerback than Stephon Gilmore because I can account for a large number of variables vis- à -vis two guys who play the same position at the same collegiate level. I can look at all sorts of physical measurements, game film against any common opponents, game film in general to get an idea of coverage skills/ball skills/attitude, interviews with each, college stats, and pretty much any other metric you can conceive. With that much information available, I can reach a fairly solid conclusion. And, if I want to extrapolate a little further, I can compare two players, decide which one is better in the abstract, and then factor in team-specific variables — defensive style, personnel, coaching philosophy or preference, etc. --- to decide which one is better for any given team. [Author’s note: unless one of your team-specific variables is "prefer the less-talented player always," the answer here will still be "Morris Claiborne."]

Now, contrast that with what I can factor in if I want to compare all the players in the draft. Physical measurements don’t work very well because you can’t directly compare a DT and a WR, so you are left comparing each player with a hypothetical archetype of a DT or WR, then comparing how each stacked up in their respective comparisons. Game film against common opponents isn’t overly handy, except in position-specific comparisons (i.e. which OT is better?). You’re ultimately left with very few variables that are universally applicable in your comparison, and you can’t even begin to factor in team-specific variables beyond the first few picks due to the number of "if Team A takes X, then Team B will look at..." scenarios that build upon one another like a choose-your-own-adventure book.

Because of this inherent inaccuracy, these general draft rankings, at best, give you a big picture idea of how to group players — that is, they give you a roadmap where you can say that these 40 or so players are all roughly equal in terms of their likelihood of NFL success, and any 32 of them could go in the first, etc. I would wager that, with very few exceptions, you usually can’t get any closer than +/- 10 as a margin of error, though I haven’t tested that part of the hypothesis.

Which brings me back to my initial point: defining which picks are or are not a "reach" based on how they match up with a small range of possible pick values is flawed from the start because it assumes a ranking accuracy that simply doesn’t exist.

Strangely enough, this problem of assuming accuracy in the rankings is exacerbated in any true "best player available" approach. Without accounting for team-specific variables, there’s no way to say that the rankings represent the "best" choices for a specific team. The SLB who is supposed to go around 15 might not be near as good a fit for your team as the kid who is supposed to go around 40, but the reliance on expert rankings such as these when determining BPA (and the reluctance to appear to be reaching) means that a team will more likely than not take the former kid.

Which means, ironically, they didn't get the best player available because they were trying to take the "best" player available.

Trading down as it relates to classically-defined "reach." An offshoot of defining "reach" as we have above is that teams talk about trading down so that they are choosing between the Y1 and Y2 range for the player they are targeting. The problem with this, as should be obvious, is that the Y1 and Y2 are arbitrarily defined, meaning that even trading down doesn’t guarantee that you aren’t "reaching" in some sense of the word. Because value can only be defined in this context after the player has played in the NFL, a pick at any position today could be seen in retrospect as a reach or a steal. While such hindsight evaluation is pretty much useless going forward, it serves to illustrate the inexact nature of the rankings.

Which, of course, isn’t to say that trading down is pointless. If you are targeting a specific player, and you know you can trade down, gain some extra draft picks, and still get your player (within N% degree of certainty, N approaching 100% in this case), then trading down is a fantastic strategic move. But that’s only if you can still get your targeted player. Assuming a correct evaluation on your part to determine which player best suits your team, getting that player at 15 (or wherever) has more intrinsic value than getting an extra fifth-round pick (or whatever) and missing your targeted player.

The other role that trading down serves, which remains somewhat independent of this analysis, is in a situation where a team isn’t enamored with any specific player, but rather has four or five that they consider equal in terms of value to the team, so they trade down with the idea of taking whichever player remains on the board when their turn comes up. This is still a valid strategy, assuming a team is not making their decision solely on whether they like or don’t like a player in the initial draft slot based on which players are "supposed" to go there.

Redefining. Before I get to my revised draft theory, we need to rework our "reach" equation to account for the uncertainty discussed above. In previous years’ versions of this theory, we have redefined it to be:

Selection of X at pick Y when X is N% likely to have been available at pick Z, where Y is your current round selection, Z is your selection in any subsequent round, and N is a percentage based on team-specific needs (including organizational risk aversion).

Now, as killtacular noted two years ago, too much reliance on organizational risk aversion here can result in absurd scenarios where teams who are not 100% sure that a fifth-round-quality player will still be around in the third round might take him in the second round. Clearly, even under our new theory, that would have to be considered some kind of reach.

Thus, in version 3.0, we took it a step further and defined "reach" as:

Selection of X at pick Y when X is N% likely to have been available at pick Z, where Y is your current round selection, Z is your selection in any subsequent round, and N is a percentage based on team-specific needs and accounting for organizational risk aversion, perceived depth at a particular position in the current draft, and historical drafting patterns (i.e. teams rarely take safeties in the first round, etc.).

Granted, this is a slightly less elegant way to define it, but I think it gets us closer to finding an optimal N% that becomes near-universally applicable. Just as with a classic definition of "reach," this newest definition impliedly carries a definition for a "good" pick.

Selection of X at pick Y when X is more than N% likely to have taken before pick Z, where N% varies depending on team-specific needs; accounts for organizational risk aversion, perceived depth at a particular position in the current draft, and historical drafting patterns; and considers whether X is seen to fill an immediate starting need (such that N% is appreciably lower if X is likely to be an immediate starter)

Again, bulkier, but more accurate.

The point of it all: The Revised Theory.

Using our new metrics, I propose a shift in the way teams approach each pick. We will use 75 and 90 as our relevant N% numbers for illustrative purposes, both because I think those numbers are pretty close to optimal and because NFL teams are conservative enough in their drafting that lower numbers would risk making this too unrelatistic:

Pre-Draft Analysis. Team determines which starting positions (or positions that get a lot of snaps, e.g. nickel corner) could conceivably be filled by a draft pick, then ranks those positions in order of priority based on team philosophy, etc.

2012 Addendum: TexansDC noted last year that there has to be a balance here between need and the perceived talent of various players. While that becomes less of an issue the lower your first-round pick is, there has to be some happy medium between addressing only the biggest issues and not passing on a superb talent that might wind up being available. For example, if the Rams had not traded out of the #2 spot, how do they balance need (WR, RB, OL, CB, LB) with the possibility of Robert Griffin III at QB? It's not an easy question to answer. So, I suppose, the point is that a team, in making its pre-draft board, has to identify the subset of players who are (apparently) so talented that the team cannot pass on them if they are available. None of these guys is likely to be available by the time the Texans pick at 26 this year, but in 2012, I think that list would be: Andrew Luck, Griffin, Claiborne, Matt Kalil, Justin Blackmon, Trent Richardson, and David DeCastro.

The other part of the pre-draft analysis that we've not previously fleshed out is the general idea of "ranks those positions in order of priority." Using the Texans again as our example, the starting and high-rep positions that could theoretically be filled by a draft pick this year are WR2, WR3, NT, CB2/3, OG, OT, TE2, K, and OLB3. Ranking those positions in terms of need requires considering the Texans' philosophies on both sides of the ball, such that a position that doesn't see the field as often (NT) is going to be less important, a position that already has a presumptive starter of decent ability (TE2) is going to be less important, and seemingly inexplicable variables like "the teams is happy with Shaun Cody and Kareem Jackson" are accounted for. Using what we know, the most likely ordering of these positions seems to be WR2, OLB3, WR3, OT/OG, TE2, NT, CB2/3, TE2, K.

Now, the part that has always been implied in this theory before (but never spelled out) is that this ranking of positional priority is only the first step. We still have to cross-reference it with the actual talent pool in the draft. Because, as we'll discuss below, there is not a consistent distribution of talent across positions in any draft, this one included. So you have to start accounting for things like what kind of OLB3 Wade prefers, what kind (read: size) of WR2/3 Kubiak prefers, and how many of each type of player is in the draft. A team also needs to honestly evaluate whether Player X would fit multiple schemes, or if he's likely to succeed only in one style of offense/defense, and the team needs to determine (to the extent possible) the likelihood that the same schemes will be run 3 or 5 years down the road. (That is, if Coach ____ leaves, how likely is the team to continue running the same or similar offense/defense?) The point being, this revised draft strategy requires more work on the front end, but it's work that successful franchises are likely already doing, even if they are not doing it in a comprehensive way that factors into their draft-day selections.

Armed with their analysis, the team can then turn to preparing for the actual draft...

First round: Team looks at all players who could fill a starting (or high-rep) slot and who are more than 75% likely to be taken before Team’s second-round pick (for example, the Texans would look at all players more than 75% likely to be taken before pick 58, which would probably include the top 65-75 players as ranked by draftniks). Team ignores players at positions unlikely to be filled by a rookie except where the position is perceived to be very shallow talent-wise in this draft or where ignoring those positions leaves a team with too few options. Team then ranks the players according to its own needs (i.e. the team-specific variables and other stuff mentioned above), ignoring the projected draft slots for each as determined by media/talking heads.

Which is to say, we use the experts’ opinions to cull the initial group from which we pare down our list, but, when making our actual list, the experts’ specific rankings go out the window. When the Team’s first-round pick comes up, the first remaining player on the list is taken.

Second round: Team looks at all players more than 75% likely to be taken between its first-round pick (to account for any players who might inexplicably slide) and its third-round pick. Same ranking process and selection process as above. [Note: It was asked in 2010 why a team should not just look at the players actually available at the time of their second pick plus guys N% likely to be gone by their third pick? The answer is because we are doing this evaluation ahead of time, and we want to know, if player G unexpectedly slides and is still on the board, how does he compare with our list. Once the pick comes up on draft day, of course you are not going to consider the guys who are missing; the point here is to consider a certain number of them ahead of time so that you aren’t thrown for a loop on draft day, wondering "oh, man, should we take this RB that we didn’t account for instead?!"]

Third round: Team looks at all players more than likely (based on the same 75/90 percentages) to be taken between its second and fourth round picks. Same process as above.

The strategy shifts a bit for rounds 4-7, as the Team looks at those four rounds as two separate groups of people instead of four.

Fouth/Fifth rounds: Team looks at all players likely to be taken between its third-round pick and the end of round 5 (because guessing this group down to your specific pick is pointless, as there are too many variables, and many of these guys, especially by the end of the fifth, are fungible to a certain extent). Rank and pick as above, with an depth at key positions becoming more and more important as a team-specific variable starting in Rd 5.

Sixth/Seventh rounds: Team looks at all players likely to be taken in the sixth or seventh as determined by a consensus of draft predictors (see…they aren’t totally useless!) as well as any players considered unlikely to be drafted, but who seem to fill a team-specific need. Rank and pick as above, with particular emphasis placed on depth above other factors.

Obviously, this approach is an attempt to get teams to take a big-picture view of the draft. Despite the apparent complexity of our formulae, at its heart, the theory is a simple one: Nothing is a reach if you are taking the best player for your team that you would not be able to get later, assuming (of course) that teams do not behave irrationally with respect to any one variable when calculating N%. The likelihoods (N%) and even some of the cutoffs for player groups, especially in later rounds, are open to interpretation and argument.

The beauty of this theory, if I do say so myself, is in its simplicity. The only important thing is targeting the best player for YOU, Mel Kiper, et al., be damned. If you can trade down and still get that player, great! If not, you take the player rather than a blind trade down. In the end, the payoff should be much greater and much more consistent, as you are applying the things important to you to a broader group of players in each round. Basically, the theory removes artificial restrictions that are inherently incapable of being accurate anyway. I fail to see how that is a bad thing, provided your team is capable of accurately evaluating talent (which is a whole other post).

To A Deeelux Apartment In The Skyyyyyyyyy. When I originally wrote this post in 2009 --- /pours out a little liquor for DGDB&D --- I noted that it could conceivably work for trade-up scenarios, though I wasn't exactly sure how. In 2010, in the extended director’s cut of this post, I attempted to work through it, only to realize through a conversation with DisplacedTexan about 45 seconds after I posted it that there were problems. I tried to address those issues in 2011, only to have NewsToTom point out a couple other tweaks that were needed. So let's address those now.

Moving (on) up requires the introduction of two more variables. First, we need to quantify the difference in terms of impact that the targeted player would have over the player currently on our roster who is slated to be the starter at that position. Quantifying such things is undoubtedly hard and requires making some assumptions that you have no concrete basis for (e.g. "This kid is not going to blow out both ACLs during camp.") To normalize, we'll translate each players' perceived value into a number between 0 and 100, where 100 is the absolute best player possible at that position and 0 is Petey Faggins. We'll call the difference between the two players "D."

The second variable is a team-specific measurement of what D is actually worth to your team based on scheme, coaching, etc. Think of it as marginal value in a football context --- we want to know how much that raw 45-point jump from Kareem Jackson to Morris Claiborne is actually worth to us. We'll call this contextualized D "D+."

How do we calculate our D+? That's where it gets a little tricky (and makes a trade-up scenario more of a gamble, really). As Tom noted last year, it's flawed thinking to assume that there is a normal distribution of prospects and talent across positions in a given draft, and this lack of a normal distribution causes a problem in our theory:

Hypo: the best safety is an 85, the next best a 65. Your current value is a 60. The best defensive end on the board is a 95. Your best defensive end is an 80. If you wait, you could get an 85. If I’m reading you right, your strategy tells you to take the safety even though the defensive end is a better player. I’m deeply skeptical of the long-term value of a strategy that advocates taking the inferior player due to superior team need.

Now, initially, I should note that I don't think this is as problematic as it appears on its face, simply because we are talking about D+ only in a trade-up scenario1. What I mean is, we're looking at this contextualized D+ to determine whether it is worth trading up for a specific player. In that case, it would not be an issue of whether we should take the higher-ranked DE or the lower-ranked S; we'd be looking at whether we should trade up to get one of them. So, applying some names to the above hypothetical, it would be a question of whether the Texans should trade up from 26 to 7 to snag Melvin Ingram, or should they trade up from 26 to 13/14 to take Mark Barron? In either case, they'd be trading up to get a specific player; in the former, they'd take the better player (Ingram), and, in the latter, Ingram would be off the board when they selected Barron.

Which is not to say that Tom's hypothetical doesn't raise some issues. It certainly does. Namely, how does one determine which of those trade-ups is more beneficial to the team (before we even calculate the overall cost to make the trade)? This, I think, is where Tom's follow-up point comes in:

A complete draft theory also needs a nuanced view of D(+) and something like my proposed V to account for scheme-specific values, the likelihood of running said schemes in the future, and a player’s short- and long-run D and V and how you balance them.

I agree for the most part. Now, I think that the scheme-specific values and things of that nature go into this equation on the front-end; when we calculated D+, we included in the definition "team-specific measurement of what D is actually worth to your team based on scheme, coaching, etc." Meaning that a player that Team 1 grades at 95 might only be an 85 for Team 2. That said, there is still definitely some room for nuance here, especially in terms of short- and long-run D and V (which is, basically, absolute value of the player in the abstract, as discussed in Tom's hypo above).

To a certain extent, this nuance is what I was trying to get at by contextualizing D to D+. As I mentioned, D+ is "marginal value in a football context --- we want to know how much that raw 45-point jump . . . is actually worth to us. " The problem, however, is that I didn't contextualize enough; as Tom notes, you have to account for other players not selected, and you have to balance talent versus need so that the fact that you have a terrible player starting at one position doesn't skew your analysis so badly that you pass up players who are objectively more talented at other positions. If you're being comprehensive, that also includes taking a look at players that you would be able to get if you didn't trade up.

Creating a universal formula here becomes difficult due to the number of variables involved in each team's contextualized D+. That's not terribly important for us at this point, however, because we're going big picture with this. To Tom's larger point about the problem of taking lesser player based on need, I think that goes back to the balancing we discussed earlier. At some point, it is conceivable that the starter you are seeking to replace is so bad that need trumps raw talent. That point, in terms of D+, is for each team to decide. Short of that point, talent acquisition should be the goal, especially in the early rounds. (Also, worth noting: as a general rule, I think you can argue that it would be a bad idea to trade up based on need only. At a minimum, a team needs safeguards in place along the lines of "only when the difference between the starter and the draft pick is >40 points" or "only when the draft pick is at least a 90.")

Anyway, fancy new D+ variable in hand, what do we have for an overall theory? To account for our new variable, the equation for a good trade-up scenario would be:

Pick of player X made at pick Y in exchange for (pick Z + value), where:

D+ of Player X > (D+ of top player you were targeting at Z PLUS D+ of average player likely to have been taken at the later pick(s) if you gave any up);
Player X satisfies team-specific safeguards for trade-up scenario;
Player X is N% likely to NOT be available at pick Z; and
No player N% likely to be available at pick Z offers a comparable D+.

That is, where the marginal benefit to your team is greater than what you have to give up to get the player, the player is good enough to warrant a trade-up in the abstract, the player is highly unlikely (N% approaching 100%) to be available with your original pick, and you can't get similar benefits from a different player by standing pat, you're in a scenario where a trade up makes sense.

The hard part here is being realistic in calculating D and D+ and being able to determine the appropriate "value" to be included with Z. Even before the new CBA, the old draft pick value chart was useless in this equation simply because of how much emphasis it placed on first-round picks. Perhaps this chart would provide a better starting point, but, in all honesty, this theory probably requires the creation of a new chart.

Burnin' Ring Of Fire. I realized as I started writing this year's version that I'd previously given short shrift to the trade-down scenario. In fact, all I'd written about it was a throw-away paragraph within the context of trading up:

Recall that our equation for trading down was, more or less, N% chance to get your targeted player at your new, lower draft position, where N approaches (but never reaches) 100%. (I realize that I am not accounting for the possibility that the value of the trade package could be high enough that failing to get your targeted player would not be a huge deal, but that is another post for another day.)

That's just laziness on my part. My bad.

As with trading up, I think there's an important need for context in determining whether it's worth moving down, and that requires some analysis of what you are giving up and what you are receiving for doing so. Now, obviously, our previous formula for trading down addressed the idea that trading down makes more sense the more sure you are that you can still get the player you want after the trade.

In the end, assuming you have a willing partner with whom to trade, the trade-down equation is easier than the trade-up version. It is basically a cost-benefit analysis:

Pick of Player X at a selection after Y where:

Player X is N% likely to be available at the later pick;
The difference between Player X and the next player on the list is within predefined tolerances; and
The D+ of the picks/players received in the trade > (100-N)(D+ of Player X).

That is, where there's not a lot of difference between the targeted player and the player you'll take if the targeted player is not there after your trade and where the value you receive is greater than the D+ of the targeted player times the risk of not getting him, then a trade down would seem to make perfect sense.

[Author's note: I'm pretty sure there's something more here that needs to be explored as far as trading down goes, but I'm not seeing it. Feel free to enlighten me below.]

Conclusion. As in previous years, I consider this a work in progress. If you drill down to the very, very basic premise of this whole thing, it is simply a way to see the big picture going into a draft. Yes, it’s also an attempt to quantify things that rarely have numbers assigned, and, yes, it requires a thorough understanding of your organization and a strong ability to evaluate talent, both currently on your team and available in the draft, but I fail to see how it is the least bit detrimental to strive for such things.

Now, not that any of you has ever needed an excuse to point out flaws in anything, but I welcome such feedback on this post. Some of those insights were integral in drafting version 4.0, and they will be just as helpful in drafting 5.0.


[1] Whether a D+ value should be part of the overall draft strategy, even in situations where a team is not looking to trade, is a separate question. It probably should, but, then again, it sort of already is, just based on how we're defining and ordering our list of players. Dunno. Something for 2013, perhaps.