Do Pitchers Try Harder for Their 20th Win?

Phil Birnbaumwww.philbirnbaum.com

July 31, 2009

Do pitchers try harder for their 20th win?

Bill James, "The Targeting Phenomenon" Historically, there are more players who

finished with one win than with two More with 2 than with 3. More than 3

than with 4 … Every number is harder to hit than the

previous, except: There are more pitchers with 20

wins than 19.

Do pitchers try harder for their 20th win?

Why? Bill James: "players WANT to wind

up the season hitting .250, rather than in the .240s. They tend to make it happen."

But HOW do they make it happen?

Do pitchers try harder for their 20th win?

Clutch pitching? Do players actually try harder

when they can win their 20th? That would mean they wouldn't be

trying their hardest in other games Not a nice theory

Season win totals, 1940-2007

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Maybe it should look more like this

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Why? Five possible factors I could think

of There could be more

Take them one at a time

Factor 1: extra starts

Maybe pitchers are given an extra start late in the season to try to get to 20

In that case, those pitchers would have a larger proportion of starts in September

Percentage of starts in September for pitchers who eventually finish with:

16 wins: 17.53% 17 wins: 17.77% 18 wins: 18.36% 19 wins: 18.49% 20 wins: 18.47% 21 wins: 18.15% 22 wins: 18.18%

-- A little bulge at 19-20, maybe 0.25%

Percentage of starts in September

The 19-20 win pitchers had 9229 starts

An extra 0.25% means an extra 23 starts

Maybe 10 wins By this analysis:

19-win pitchers, circumstances created 10 fewer (-10) of them

20-win pitchers, 10 extra (+10)

Factor 2: relief appearances

Maybe 19-win pitchers got a relief appearance to try to reach 20

Check the historical record Big metaphorical wet kiss to

Retrosheet

Factor 2: relief appearances Eventual 20-game winners with relief wins:

1951: Early Wynn wins 18th

1951: Mike Garcia wins 19th

1956: Billy Hoeft wins 20th

1957: Jim Bunning wins 20th

1966: Chris Short wins 20th 1991: John Smiley gets 19th

1997: Randy Johnson gets 20th

7 extra wins

Factor 2: relief appearances

Eventual 19-game winners with relief wins: 3

Eventual 20-game winners with relief wins: 7 (previous slide)

Eventual 21-game winners with relief wins: 6

Take these numbers at face value, since they're exact historically

Factor 3: clutch pitching

The obvious question: did they just pitch better with 19 wins, with the 20th on the line?

How did the pitchers actually perform with various numbers of wins?

Team RA and win pct. for pitchers 17 wins: 3.72 RA, .658 18 wins: 3.54 RA, .652 19 wins: 3.54 RA, .655 20 wins: 3.62 RA, .615 21 wins: 3.53 RA, .676 22 wins: 3.34 RA, .774

(Note: RA is for team, not just the starter; wins are at the time of the start, not at end of season)

Only a tiny bit of difference – maybe .08 RA? I feel better; pitchers are still team players

Team RA and win pct. for pitchers

Move the 20-win group from 3.62 to 3.54

Difference: 39 runs over 490 starts – 4 wins

Four 20-win pitchers "should have" moved to 21 wins

So four extra 20s, four fewer 21s

But wait!

The 20-win group's RA was only a bit higher than you'd expect …

But their winning percentage was much, much too low!

18 wins: 3.54 RA, .652 19 wins: 3.54 RA, .655 20 wins: 3.62 RA, .615 How come? Run support.

Factor 4: run support

19 wins: 3.54 RA, .655, 4.45 RS 20 wins: 3.54 RA, .615, 4.05 RS 21 wins: 3.62 RA, .676, 4.46 RS Holy crap! After achieving their 20th win,

pitchers' batters let them down in their tries for 21

A huge 0.4 run per game shortfall!

Factor 4: run support There were 490 starts by pitchers with

exactly 20 wins 0.4 runs per game is 196 runs That's 20 wins! Maybe 15 of those wins

would have gone to the starter So 15 pitchers got "stuck" at 20 wins

instead of moving to 21 That's an extra 15 twenty-game

winners, and 15 fewer twenty-one-game winners.

Factor 5: more decisions Maybe when a pitcher is going for 20,

the manager will leave him in longer Looks like it! Wins per start, 17 to 22

wins: .484, .496, .521, .463, .505, .554 Suppose they should have been .505.

That's 11 extra wins. So we have an extra 11 twenty-game

winners, and 11 fewer nineteen-game winners.

Totalling it up

Starts Relief Clutch

Support

Decisions

Total

19 –10 +3 –11 –18

20 +10 +7 +4 +15 +11 +47

21 +6 –4 –15 –13

One last adjustment However: some of these pluses and minuses

need to "move up" a category Example: a manager gives his starter an extra

relief appearance; he wins his 20th. But five days later, he wins his 21st.

We think that should be a move between 19 and 20, but it really wound up as a move between 20 and 21

I'm arbitrarily going to adjust 19s: from –18 to –16 20s: from +47 to +37 21s: from –13 to -7

Final score

Final total: 19 game winners: –16 20 game winners: +37 21 game winners: –7

If we back all these effects out of the original data, there should be no more bulge at 20

Not perfect, but not bad

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Summary By this estimate, there were 37 "extra"

20-game winners compared to expected. 10 because of extra starts in September 7 because of relief appearances in

September 3 because 20-game pitchers didn't pitch well

enough to get to 21 11 because 20-game pitchers got such bad

run support that they couldn't get to 21 6 because managers left the pitchers in

longer in hopes they'd get their 20th that day.

Summary

So is it because pitchers want it to happen?

No; it's mostly because managers want it to happen.

Broken down: +23 manager decisions; +3 pitchers pitching worse when already at

20; +11 run support luck.

Reference Bill James, "The Targeting

Phenomenon," The Bill James Gold Mine 2008, p. 67