BP Unfiltered

Just out of curiosity, with Matt Swartz bringing Siera over to Fangraphs and presenting new updates to the stat over there, will BP be incorporating these updates? Or, has other staff taken up providing tweaks to Siera? Is the Siera presented here going to diverge from the Fangraphs Siera?

I am a huge longtime fan of BP. I'm very frustrated. Y'all are better than this. Or maybe not.

I appreciate the general admission of errors, but there are some specific unacknowledged errors that ought to be addressed.

1. What makewayhomer said.

1a. You started the RoS PECOTA by announcing that "Fangraphs is wrong." Now you've apparently gone toward Fangraphs. My quick calculations indicated Fangraphs' weighting was pretty good; rather more tellingly, Tom Tango's did too. I'm pretty sure an apology is in order; if you're going to wrongly disrespect competitors, you owe them an apology when you're wrong.

This is really bad form not to do that.

2. If you're going to talk about PECOTA problems and not address the Kila/Bowker problem - which was obvious and mentioned at the time by more than one person - that seems unfortunate. Some indication that you're trying to repair the error would be nice.

3. If you're going to talk about PECOTA problems and not talk about the Trout problem, that seems unfortunate. Some indication that you're trying to repair the error would be nice. The continued insistence at the time that the comp list problems for those with recent minor league histories weren't problems was very annoying, and remains so. One of PECOTA's great assets has left the building and there's no indication that it's coming back.

4. There's an ongoing bug in the A's in the Playoff Odds for at least a week. The Rockies are similarly problematic due to a Mark Ellis bug. Someone should look at these intermittently.

5. The way Nate did the Playoff Odds, if I understood it correctly, was to assume team quality around a baseline; the Monte Carlo sim used a distribution of quality assumptions vs. the remaining schedule. (That is, if we assume the A's are a .642 team the rest of the way, the sim might play them out as .655 or .617, rather than just as .642.) The playoff odds report appears to neither assume a distribution of potential goodness nor does it appear to take schedule into account. I could be wrong about this.

Short version: Grownups acknowledge error. I get that you want to sell the product, but there are some of us in the unwashed masses who aren't buying diet pills from Steve Garvey, penis extensions from Jimmy Johnson, and Fangraphs is Wrong from BP. Admit specific screwups.

I want to love you guys. And there are lots of good articles. And it makes me happy that Team Tracker's improved in some details (if not in daily reliability.) But you're making it hard.

--JRM

I appreciate the update. But I am still left to wonder: what is the current status (and future) of the missing 10-year player projections?

Hi Colin

If this is going to be a general gripe with the stats, I'd like to add something. I've been disappointed by the disappearance of Clay's minor league translations.

I was shocked to recently learn that he's posting them at his own website and is apparently no longer involved at BP? Who would know as we've never been told.

To the extent that you want to get into that issue is up to you, but I must say I very much miss having something like those reports available. Are there any plans to provide something similar in the future? If not, why not?

Thanks.

question - only tangential related to pitching stats - is the FLAKE stat still posted?

Colin,

I think you have a bug with the "rest of season" (RoS) forecasts. I remember a while ago, Felix's RoS was 2.30 ERA, which was quite bold, considering that:
a) his mean forecast entering 2011 was around 2.60
b) his season performance to then was worse than 2.60

So, given more information, his RoS should have been somewhat worse than 2.60.

Now, his RoS is even lower at 2.19:
http://www.baseballprospectus.com/card/card.php?id=HERNANDEZ19860408A
That is even bolder since his current performance is basically a match to his career totals, and so, you'd need to have his mean forecast be higher than 2.60.

His RoS is a 3.2 WARP, on RoS 98IP. His WARP in his Cy season was 4.4 (250 IP) and 5.6 in 2009 (239 IP).

***

Also, the percentile forecasts are showing this timestamp:
Last Update: 3/26/2010 14:48 ET

Note the year (2010, not 2011).

Tango, I will go ahead and review Felix's forecast to make sure there's nothing going on there. But comparing his RoS forecast for 2011 to his career stats is misleading, given the significant drop in league ERA. For Felix's career prior to 2011, weighted by his IP, the league average was 4.39. The league average for 2011 is 3.87.

In Felix's case, there's also the change in park factor at his home park. Seattle has gone from being a modest pitcher's park from 2006 through 2009 to being essentially the AL's new Petco in 2010. I find myself curious as to what's driving the change in Seattle - whether some of it is changes to the park itself, versus changes to other parks around the league - but I'm fairly convinced that this is a substantial change, not just a data artifact.

As for the timestamps, that's just a typo. We'll get that fixed.

Since I was mentioned twice (for each side!), here is the thread I have on my blog.

My explanation as to how to do RoS is in post 9. And, I agree in post 12 that you can't keep the weights constant.

Dan chimes in in post 14, and if you look at that post and the link in post 10, it sounds like Dan implemented his weighting scheme (irrespective of actual PA) as a quick effort to get something rolling for this year. I'd expect Dan to improve upon it for next season.

***

In any case, of all the things where we have disagreement in the saber community, weighting of performance by timeline is not one of them.

The weighting of daily performance ALL will follow something along the lines of:
weight=.9994^daysAgo for hitters
weight=.9990^daysAgo for pitchers

That is, the further back in time, the less weight. You can quibble about whether to use .9992 or something for hitters, etc, or, that you want it to accelerate faster, like:
weight = .9998^(daysAgo^1.2)
but, basically, we're all dancing around that scheme.

***

I agree with Colin that all discussions should take place out in the open. It makes life easier, and 2000 heads are better than 2.

my head hurts