What is the stat pLI?

[Herolover12]

Under pitching stat I see the stat pLI, but I can find no information on this stat. What is it?

[Herolover12]

Ignore and delete found it.

[micropterus58]

Just in case somebody else wants to know. Players Leverage Index.

https://library.fangraphs.com/misc/li/

[NoOne]

this is the bad side of stats... you can have all sorts of sophisticated, elegant algorythms and advanced metrics, but it doesn't mean it tells you anything meaningful.

this is something related to "clutch". in reality, all this is doing is created an extremely small sample size with insanely high volatility, especially in any given year, and likely not enough in the course of their career in an amount of time to make it useful before they are an old has-been.

i had no idea what that was, either :P

just like it's a horrible idea to go spend wildly on some guy that performed well in the playoffs, even if multiple years. the truth will out. he simply had a good 2-weeks, which can happen at anytime over 162 games, and means nothing if it happens at the end of the year as far as how good tha tplayer is or is not.

[Matt Arnold]

Leverage index is actually less like clutch and it's more a simple function of usage. Basically, a high Li means the guys was often brought in tight spots. Low LI means he was used more in a mop-up role.

[Herolover12]

Originally Posted by Matt Arnold

Leverage index is actually less like clutch and it's more a simple function of usage. Basically, a high Li means the guys was often brought in tight spots. Low LI means he was used more in a mop-up role.

After I found out what it was this is the way I took it.


In my very uninformed opinion this is one of those stats that is interesting, but not something I am going to put a great amount of weight to.

[CBeisbol]

Originally Posted by NoOne

this is the bad side of stats... you can have all sorts of sophisticated, elegant algorythms and advanced metrics, but it doesn't mean it tells you anything meaningful.

this is something related to "clutch". in reality, all this is doing is created an extremely small sample size with insanely high volatility, especially in any given year, and likely not enough in the course of their career in an amount of time to make it useful before they are an old has-been.

i had no idea what that was, either :P

You still don't, it appears

As Matt Arnold said, it tells you WHEN a player was used, it tells you nothing about HOW they performed.

This is the problem with criticizing something that you don't understand

No stat is any better or any worse than any other. There are only good and bad applications of stats.

Take, say, batting average with runners in scoring position. It, simply, tells us what a player's batting average with runners in scoring position is. But, a lot of people conflate this with a player being clutch, or not clutch. As if how a guy hit in a 10 run game with a runner on second somehow says anything about clutch while ignoring how a guy hit leading off the bottom of the ninth down by one.

LI, leverage index, tells you how important a game situation is. With 1 being average and higher numbers being more important.

For example the highest leverage PA in last night's game came in the top of the seventh, with the Nationals up 3-2, the bases loaded, and Howie Kendrick at the plate. FanGraphs had an LI of 3.06 for that PA. The second highest LI in that game was in the bottom of the sixth, with the score tied, one out, two runners on, and Carlos Correa batting. Anyone watching the game could feel the importance of those two situations. And Kendrick delivering and Correa coming up empty had a huge impact on the game. pLI is the average of all the PAs a player faced over a given time frame.

https://www.fangraphs.com/plays.aspx...am=Astros&dh=0

I hardly ever use pLI. If I do look at it's usually to look at how a manager is doing. Is he using his best relievers in the most important spots, or is he wasting his best relievers in unimportant situations and leaving lesser players for more important ones.

It can also be interesting to see how a relief pitcher's use changes. Maybe a rookie comes up and is used in low leverage situations at first, but by the playoffs the manager is using him in more important spots. Or, vice-versa, the aging closer is falling out of favor.