Library Update: RE24
For readers who prefer context-dependent statistics, there aren’t many better options than RE24. Despite the statistic’s popularity, our explanation of the statistic was previously housed in a few separate blog posts rather than one entry in the FanGraphs Library. Today, that changes with the newly minted entry for RE24.
RE24 is based on run expectancy and the 24 base-outs states and tells you how many runs above or below average a player has been relative to the situations in which they have been placed. You can head over to the Library for a full breakdown, but feel free to post questions in the comment section of this post or contact me on Twitter @NeilWeinberg44 for any related or unrelated questions about RE24, FanGraphs, or advanced statistics. Also, be sure to check the Library for updates and blog posts about the site and our data.
Neil Weinberg is the Site Educator at FanGraphs and can be found writing enthusiastically about the Detroit Tigers at New English D. Follow and interact with him on Twitter @NeilWeinberg44.
Awesome post, Neil. Thanks!
I’m liking your work, Neil.
Why would someone prefer RE24 to WPA? Can’t figure it out.
I’ll take a crack at this. I believe it is because RE24 doesn’t care about the score. A grand slam always has the same RE24 value. The WPA for a grand slam would be dependent on the score of the game when it happened.
I like to think of RE24 like a better version of RBIs.
It seems to me that you’d prefer either WPA or wRC+, while RE24 is kind of between those two.
And this is the problem with RE24, right? That’s it’s still a version of RBI? So players who bat 3rd and 4th will be favored over those who hit 1st, for example, because they’re able to be “run producers.” And players on teams that happen to score a lot of runs end up with higher RE24’s because their teammates are better. Am I right?
Don’t get me wrong, I like RE24 fine for what it does but I still prefer wRC+ when comparing offensive players.
Not exactly. Because you get credit for how well you do compared to the expected number of runs. So if you’re a #3 hitter who gets into lots of good situations, failing in those situations is equally as costly as succeeding in them is beneficial (or thereabouts). In RBI, you can never lose an RBI. If you fail to deliver in a bases loaded spot, you are docked RE24.
And personally, I also prefer context neutral numbers. This is a compliment not a replacement.
let’s look at ryan howard’s 2014. dude has 63 RBI. that’s amazing! he must be amazing!
wrong. he has a -0.30 RE24, which means that an average batter (not even just first basemen) would be expected to to produce 63.3 RBI in those same situations that ryan howard has been in.
ignore what i said. it doesn’t quite work like that.
RE24 tells you the degree to which an event influenced the number of runs a team was likely to score. WPA tells you the degree to which an event influenced the odds of a team winning.
Those are different questions. RE24 is more about the situations within an inning and WPA is more about the overall situation within the course of a game.
So wRAA is totally context neutral, a double is always worth the same.
RE24 is somewhat context dependent and a double will be worth more with men on base.
WPA is totally context dependent, so a double in a close game is worth more than one in a blowout.
Different questions, different stats.
I understand the difference. But why would you only want the context of runs, not wins? Runs are only important as far as they lead to wins.
What’s more valuable, hitting a leadoff home run in a 1-0 win or hitting a walkoff home run in a 1-0 win?
WPA gives you more credit for contributing to run scoring based on what else has happened in the other innings of the game. That makes it a story stat. It tells you how much the odds of winning changed, but it doesn’t tell you anything how good a player was.
If the leadoff home run leads to a run, it leads to a run. The player doesn’t control what the other hitters and other teams does for most of the game. So it tells you what happened, but it won’t give you an accurate reading for a player’s skill or contribution.
WPA would give more credit to the walkoff, even though it was the exact same event.
neil, is a player’s total RE available anywhere?
i was thinking (RE + RE24) / RE would be an interesting stat since players coming to bat with men on have higher potential for their RE24. the only way i can see to find RE currently is using the play log on an individual player’s page.
thanks in advance!
I don’t know of anywhere where you can find the information in that form. You’re essentially trying to build a rate state for RE24? Like a RE24+.
There have been a few attempts at similar things. Look up wOBA24 or bowOBA. I like where your head is, in looking for a rate stat but RE24 per PA is probably your best bet for now.
Hi Neil,
Good stuff. Could you get that added to the glossary blogs? Last entry is still your wRC+/context piece from last week.
Thanks
The RE24 entry is build into the actual glossary. http://www.fangraphs.com/library/misc/re24/
To get RE24+, it would work the exact same way in turning wRAA into wRC+.
Two comments/questions on this, Tango.
RE24 is already park adjusted, though. So the park-adjustment isn’t needed.
Also, how do you work the denominator? Would you use a context neutral number? So you do (RE24/PA + LgR/PA) as the numerator, but League Specific wRC/PA in the denominator? Does that cover it? That doesn’t exactly seem right, but I could be missing an obvious reason.
Here’s a useful link:
http://www.fangraphs.com/blogs/re24-insidethebook-com/
Check the comments too.
This is linked in the main entry too, for those of you who have read it.
I’m curious the mechanics of the RE tables. For the first play of the year, do you use the previous year’s RE table? Is it a rolling (Say last 162 games in the park)? At the end of the season do you go back and re-run the stat using the full season’s RE by park?
We use last year’s run environment based on total runs scored in that park. I know we have plans to tweak it a little this offseason, but you’d only notice the changes at the extremes I think.
Could anyone answer the question I’ve had for a while now: Why has tERA been removed from the player pages?
It was basically a less developed version of SIERA
My understanding was always that they serve different purposes: SIERA is normalized based on a pitcher’s profile, while tERA is based strictly on the linear weights of various batted-ball events; FIP:xFIP::tERA:SIERA, if you will.
Also, are there equations for tERA and SIERA published anywhere?