revolutionary tools.  groundbreaking articles.  proven results.

RotoViz 101: Which NFL Team Stats Are Predictive (And Which Aren’t)?

In this series of posts I’ll discuss which of the various box score and advanced stats forecasters should pay attention to when projecting teams and players into the upcoming season.

Player projections begin with opportunity. The overall league offensive environment is important, and it’s one that Ben Gretch has looked at already this offseason. To get a sense of what opportunity will be available, either via targets or touches, you typically forecast each team’s total play count, along with a run/pass percentage split.

This is actually fairly difficult to do accurately. It’s even harder if you use the wrong metrics. Since perhaps the biggest error an analyst can make is to confuse a descriptive stat (“here’s what happened”) with a predictive stat (“here’s what may happen in the future”), I compiled a list of various offensive and defensive stats and tested how well they predict themselves year-over-year.

To test the year-over-year predictiveness I used r-squared. It can be thought of as a measure of the stability, or stickiness, of a particular stat or metric. Stable metrics are always better for forecasting. They allow us to tether our evaluations and opinions to firm analytical ground.

Conversely it is extremely valuable to know which stats and metrics are unstable, or subject to huge variance year-over-year. As analysts we can discount these and try to account for the unknown they represent in our models.

With all that out of the way, here are the year-over-year r-squared values for 29 defensive and 32 offensive stats and metrics with (bonus!) completely arbitrary color-coding.

Notes

  • Efficiency, on both sides of the ball, is highly variable. I’m sorry I can’t type that with a straight face. Efficiency is a shit-show. No, that isn’t quite right. It’s a monkey-filled shit-throwing clown-circus led by a drunk ringmaster. Better.
  • If you use year-N Defensive DVOA to help you project strength of schedule in year N+1 you are making a terrible mistake. DVOA is a wonderful metric for telling us how a defense performed the previous year. It tells us nothing – literally – about how a defense will perform in the future.
  • Defenses that are attacked through the air in year N tend to be attacked through the air at vaguely similar rates in year N+1. We can probably use this as a proxy for “good defense to start QB/WR/TE/pass-catching RB against.” Note that this may mean the team has a very good offense that causes the opposing team to play catch up in the second half, and not that the pass defense is necessarily bad.
  • Rushing is a crap shoot. This has massive implications for RBs. It also poses questions about just how much a run-blocking offensive line is worth.

Conclusion

There are other takeaways from the data, but they mainly concern how you should approach modeling the NFL. In general, we can predict volume decently. In general, we cannot predict efficiency in any meaningful way. It follows then that our projections should take a range of possible volume projections and multiply them by a range of possible per-unit outcomes. A great way to do this is with Bayesian modeling using beta and gamma distributions as priors, or with RotoViz’s similarity score apps.

Find An article
Generic selectors
Exact matches only
Search in title
Search in content
Search in posts
Search in pages

recent and related...

in case you missed it...

Don’t Miss Out on the Best WR Value in the 2019 Class

  Andy Isabella may be one of the best rookie values in recent memory, but he’s not the best WR value in this draft class. No, that honor goes to a different senior WR from a non-power 5 conference. One who actually broke out before he was 22 years old.

Read More

3 Players You Should Stop Drafting at ADP

  Being player agnostic is one of the best edges you can find in fantasy football in 2019 — don’t fall in love with a player, fall in love with his price. With the suite of RotoViz tools, finding this year’s most mispriced players is easier than ever. We already

Read More

3 Value IDPs I’m Targeting in 2019 Rookie Drafts

Dynasty rookie drafts are in full swing this spring, and if you’re like me, it’s not enough to just play in an IDP league — it’s got to be a deep IDP league, requiring you to unearth rookie gems on a regular basis. In the midst of a dynasty rookie

Read More

High-Stakes Dynasty Startup Picks to Exploit and Avoid

On the heels of Cort Smith’s posts identifying the overvalued picks and standout sleepers according to Fanball (formerly MFL10s) ADP, we’re using the Dynasty ADP app to find similar trends in FFPC start-up leagues. Because, as Cort points out in his pieces, don’t love the player, love his price. This

Read More
Connect
Support

rotovizmain@gmail.com

Sign-up today for our free Premium Email subscription!

© 2019 RotoViz. All rights Reserved.