Get To Know: F-Strike%

F-Strike% (first pitch strike percentage): The percentage of plate appearances (for batters) or batters faced (for pitchers) that the first pitch was a strike. This includes anytime that the count after the first pitch was 0-1, or anytime the ball was put into play on the first pitch of a plate appearance.

Why you should care: Getting the first strike on a batter significantly decreases the batter’s chance of success and likewise increases a pitcher’s chance of success.

Current Baselines
: The major league average F-Strike% for all players from 2005-2008 is 59%. There is very little variation in the major league average from year to year.

Batters: A lower F-Strike% is preferable for batters.
Pitchers: A higher F-Strike% is preferable for pitchers.

Links and Resources:
Hardball Times: The Importance Of Strike One (Part One)
Hardball Times: The Importance Of Strike One (Part Two)




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David Appelman is the creator of FanGraphs.


9 Responses to “Get To Know: F-Strike%”

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  1. jlebeck says:

    D.A. says “Batters: A lower F-Strike% is preferable for batters.”

    I get where you’re going with this, but if F-Strike includes balls put in play (btw, do you count HR in this?) doesn’t it muddy the water just a bit? If a guy is thrown a strike on the first pitch, but rips the heck out of it, that shouldn’t be looked at as a demerit against the batter.

    I think F-Strike% has much value, but it just feels like there needs to be more info to really utilize it.

    Not sure I’m articulating what I’m thinking though.

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  2. Terry says:

    S-strike% (second strike %) would be a more powerful measure-it’s the strike that really swings outcome.

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  3. jlebeck: I definitely see what you’re saying here. It’d be easy enough to exclude home runs, which would seem be a fair thing to do. Also, I don’t think the stat is intended to be used on it’s own, but it’s something I see people talking about enough that I thought it’d be a good addition to the plate discipline stats group.

    Terry: Here’s an excerpt from the THT article: “The chart above will confirm that the impact of a strike versus a ball on a 1-1 count, is greater than that on a 0-0 count. The 1-1 strike is worth .092 linear weights runs to the pitcher, while the 0-0 strike is worth only .069 runs. But comparatively, the impact of 0-0 strikes is almost twice that of 1-1 strikes. This is because while there were 175,638 plate appearances that included 0-0 counts, there were just 68,748 that went to a 1-1 count. If you emphasize the importance of 1-1 strikes to a pitcher, but de-emphasize the importance of 0-0 strikes, he will not do as well.”

    It’s true the second strike does have more of a swing, but I’d argue the first strike is still the most important.

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  4. Terry says:

    If looking at a PA as a battle, it’s clearly strike two that dramatically swings the advantage to the pitcher.

    Strike one is important because strike two can’t occur without it but as an end all, strike one isn’t the leverage event that F-strike% might suggest. Arguing that the first strike is more important to determining the outcome of a PA because of opportunity kind of obfuscates the reality that strike two is the sledge hammer.

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  5. Steve says:

    David, thanks for answering my email. Thinking about this a bit more, I wonder if you have the data for conditional plate discipline stats for when a hitter’s ahead (3 balls, less than 2 strikes) and when he’s behind. (less than 3 balls, 2 strikes) High leverage counts could show the finer skills of a player’s plate discipline as opposed to the aggregate numbers by themselves.

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  6. Steve, you’re right that breaking down the plate discipline stats (especially O-Swing%), by count would definitely show the fine details. You’d see how each batter expands the strike-zone on different counts. I did an article in 2006 about just that: http://baseballanalysts.com/archives/2006/12/expanding_the_s.php

    Here’s the O-Swing% by count from that article:

    Count         OSwing         ZRatio
    0-0           11.33%           1.15
    0-1           22.54%           0.83
    0-2           31.57%           0.51
    1-0           18.61%           1.31
    1-1           26.78%           1.05
    1-2           37.37%           0.70
    2-0           16.38%           1.61
    2-1           28.58%           1.41
    2-2           41.40%           0.98
    3-0            2.69%           1.73
    3-1           23.37%           1.67
    3-2           44.86%           1.57

    Unfortunately, this isn’t something I can show for every player at the moment. There are limitations with how I can use the data on the site and the way things currently are is the best I can do for now.

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  7. Steve says:

    Gotcha. Thanks, David. Once again, thanks for adding the plate discipline stats for pitchers.

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  8. Mark says:

    You got an article like this for every FanGraph statistic?

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  9. cpt. obvious says:

    T-strike% (third strike %) would be the most powerful measure

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