LEBRON is also using BBall Index's "player role stuff" to influence the prior, not just boxPIPM (I helped Krishna put some of LEBRON together, and did most of the backtesting).
With respect to their luck adjustment as flagged by
@slamminsammya - I agree this is DIPS-like, and drops meaningful data because we don't yet know how to quantify it. On the other hand, DIPS remains hugely influential (probably the most influential sports stat finding of my lifetime), and is like ~85% true in the purest Voros form. We're probably in a similar place on luck adjustments right now. We're losing meaningful signal by adjusting opposing shooting percentages, but
mostly we're getting rid of noise, such that it's worth it on net.
In my testing, it's a good stat,
in the top ~3 most predictive public metrics at predicting future game outcomes (along with my own
DARKO, and Taylor Snarr's EPM). I do agree there's a somewhat unfortunate proliferation of these stats right now, which leads to some cherry picking to find the stat which best fits the narrative someone wants to tell. I don't really know the answer to that issue, and I'm not obviously not helping myself (although DARKO is a bit different, in that it's fundamentally predictive).
Some quick specific thoughts:
- I don't think RPM should be cited anymore. There have been some significant changes to the metric recently since the creator was hired by the Mavericks. Nobody has a real understanding of what the stat is doing anymore, and it doesn't perform well in testing.
- The same goes for RAPTOR. The stat has not held up well in out-of-sample testing, and is prone to wild swings in the playoffs in particular. I respect 538 a lot, but they're not an NBA shop, and don't seem to put in consistent effort to keeping RAPTOR reliable. They have also made some strange decisions in not running a true RAPM model here.
- BPM remains useful in my opinion for being a box-score-only metric. If you see a player doing well in BPM, but poorly in LEBRON or EPM, that's a sign that their on-off data is not very good for instance. It's helpful in adding interpretability to understand what's going on with some players. Note VORP is the same thing as BPM. It's just the counting stat version. Your VORP is a linear function of your BPM and minutes played.
- RAPM is likewise useful as a pure on-off stat. It's the complement to BPM, ignoring box stats entirely and just surmising how good a player is from on/off data.
- Nobody takes PIE seriously.