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Examining draft day trades and the value they hold: Part 3

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Despite the age of the Johnson chart, it continues to predict high-end trades better than its competitors. However, a new chart is beginning to own the middle of the draft.

Chicago Bears Introduce Matt Nagy Photo by Jonathan Daniel/Getty Images

Previously, when I have looked at draft trades, I have defaulted to the Johnson chart, which many people consider outdated. The reality, however, is that the Johnson chart is still largely accurate. For example, for the 105 draft trades that have taken place in the last three years, the Johnson chart has been within 5% of the predicted value in 54 cases and within 10% in 78 cases. That’s remarkable for such an old instrument, and most of the “errors” come from the end of the chart, where picks in the fifth, sixth, and seventh rounds are being swapped hastily. There is less value to be found in these picks, and so a few points of irregularity here or there make a bigger swing in the total percentage of value lost or gained.

Of course, another advantage to using the Johnson chart is that there are calculators readily available online to help determine pick value, and so I only need to check the math--I do not need to do it all by hand myself. The only other chart system that has such convenience is the Chase Stuart chart, and that is simply not a tool that matters when it comes to predicting which picks will be traded for what value. I’ve covered this before, and it remains true.

However, there is a third option, and that option comes in the form of the work done by Rich Hill. Hill writes for Windy City Gridiron’s sibling site, Pats Pulpit. Hill has a new chart, more or less reverse-engineered from trades that took place after the new CBA went into effect. It attempts to construct how actual GMs value actual picks, and so it is functionally superior to the theoretical work done by Stuart. Using the sample of the last three years of pick-only trades, and using the version of Hill’s chart available through Drafttek for 2019, we find that Hill is within 5% of the predicted value of picks 55 times, and within 10% of the predicted value 80 times. In other words, he had two more “hits” about the Johnson chart. That’s nice, but it’s also unspectacular.

What gives?

Hill vs Johnson

To some extent, the Hill chart encounters the same problems as the Johnson chart. Essentially, both charts hold up impressively well across the first couple of rounds, but in later rounds things get messier. Most of the big misses involve picks after #150, and they deal with very slim total margins.

For example, the Johnson chart only misses by more than 10% on 3 trades out of 32 in the first two rounds. One of these is the ridiculous overpay the Jets made to trade up to spot #3 in 2018, and another is Panthers overpaying to trade with the Seahawks in order to take Greg Little. The final miss? The Bears got too good a deal on their trade to draft Anthony Miller in 2018.

Meanwhile, the Hill chart misses with those three picks as well. However, it also misses on other picks at the top of the draft. The Hill chart has the Bears as underpaying the 49ers by a considerable degree (they paid 89% of the Hill chart’s value for #2, whereas the Johnson chart has the Bears/49ers trade as almost a perfect breakeven proposition), and it also has the Bills as overpaying the Bucs by 29% to draft Josh Allen. Additionally, it thinks the Steelers overpaid the Broncos by 18% to take Devin Bush. These three trades are fine by Johnson’s chart.

Why the difference? I think Rich Hill is trying too hard to make sense. When he is using past trades to calculate current value, an even mathematical progression of value makes sense. However, GMs do not seem to value picks in the top ten evenly. They place disproportionate value on them, and that means that the steep curve of the Johnson chart is more likely to hold up precisely because it does not make as much “sense” in objective terms.


On another note, it is worth pointing out that across these three years, the Patriots are the team most likely to give away higher picks for less than what Hill predicts their market value to be, followed closely by the 49ers and the Jets. Obviously, with high-end picks being overvalued by many measures, it makes sense that some teams would accept a lower price. However, just because it seems to work for the Patriots does not mean it is a proven strategy, as the other two teams on that list prove. It’s hard to claim the strategy adopted by San Francisco and New York are netting them impressive results, at least so far.

By contrast, it is interesting to note that only one team has multiple trades forward where its GM beat the Hill values over these three years, and that’s the Chicago Bears’ Ryan Pace. On the other side, only one team was able to get an above-predicted return for selling its pick more than once--the Baltimore Ravens. Finally, only the Buffalo Bills overpaid more than once. However, there is not a lot in the way of “pattern” beyond that. Essentially, the Johnson chart, or something like it, holds sway across most of the draft. Rich Hill is getting closer and closer to cracking the code on the new values GMs are using post-2011 CBA.

Ultimately, nobody is owning the trade market, but an argument could be made that Ryan Pace is doing a better job than most of his peers in maneuvering through the draft. It is also true that there is no obvious sign that teams succeed or fail on the basis of how they trade. For example, the Patriots have both overpaid to trade up and taken less than market value to trade down. However, they seem to be doing fine. The Bills and Jets have the same pattern, and they cannot boast nearly the same outcomes.