Weird ESPN QBR ratings

[sp6488]

On 12/21/2017 at 4:30 PM, Cakeshoppe said:

This is a very good post. If you have a stat you agree with all the time, you run the risk of having a stat that isn't telling you anything. If we want advanced stats to have value, they should tell us something we don't know, and hence it should sometimes produce unintuitive results. Otherwise, it's just a way to make arguments look more convincing. So sometimes useful stats will be unintuitive and that's a good thing.

 

My big problem with QBR is that it's black-boxed. We don't get to see what their weightings are for any of the inputs and so then we just have to take their word that the outputs are telling us something useful when they don't accord with our intuitions. With something like Passer rating, which is very transparent, or DVOA, which is gray-boxed (we can't compute it ourselves but at least we know their methodology for computing it), at least we can look at the assumptions that go into it and decide if we agree with them. With QBR, when it spits out something really odd, we have no idea if it's telling us something valuable but unintuitive or if we're just seeing  a product of the problems we already know are built into it. 

This is it for me. 

Also despite its flaws, passer rating, which really should be called "passer efficiency rating," does exactly what it purports to do.  As long as you realize that it's basically positively correlated with Y/A, TD% and INT% (well negatively on the last one), and doesn't necessarily tell you who played "better", you're fine.  Often times, IMHO, its most valuable to have metrics that are flawed or limited in some way, but do what they are good at very well, rather than trying to find a comprehensive metric that tells you everything.  Passer rating allows us to easily compare context-neutral efficiency for QBs.  If you just leave it at that, its quite useful to quickly get a sense of what it measures. 

[Iamcanadian]

I'm pretty sure I read that QBR includes their running stats as well as their passing stats and that is why QB's who can run effectively will always rate high in this category.

Of course, a franchise QB is usually a great passer, but may be useless as a runner, so in fact, this stat is pretty well useless when measuring a QB's ability and no HC, DC, GM or scout, would ever give it a second look when considering how talented a QB is?????