Baseball HR and SO over the years

From my upcoming Masters thesis, in baseball over the years, Home Runs (HR) and Strikeouts (SO) have been highly correlated (0.85).  Graphically we see this (values are scaled):

HR and SO by Year

HR and SO by Year

The Bill James Historical Baseball Abstract mentions a jump in HR’s in the 80’s and a jump in SO’s in the 90’s.  We see both of those here.  Perhaps most interesting is that for the 80’s HR spike, SO’s didn’t really keep pace that decade.  As James points out this was the first decade where players could finally make enough to play full time and work-out year round instead of selling cars in the off-season.  And of course there was probably drug use.

So you would think that if the wind were to have a significant impact on HR’s, you’d see its influence on the HR but not a corresponding influence on SO:

HR by Wind Direction

HR by Wind Direction

When the wind is blowing out at Fenway (Southwest wind) it does in fact appear as if there a slightly more HR’s.  Still the affect is hard to quantify.

Rare Events at Fenway Park

My thesis dataset includes the 3,231 games played at Fenway Park from 1970 to 2009.  While doing exploratory analysis it got me wondering about what are the rarest events that have happened at Fenway in 40 years.  Intuitively, I thought Catcher Interference or Balks, but once again intuition is wrong:

Play Count Avg
Triple Plays                       9         0.003
Catcher Interference                    19         0.006
Balk                  245         0.076
Passed Balls                  657         0.203
Triples              1,251         0.387
Caught Stealing              1,675         0.518
Sac Hit              1,725         0.534
Hit by Pitch              1,843         0.570
Wild Pitch              1,860         0.576
Sac Fly              2,017         0.624
HR              6,197         1.918
Hits            62,130      19.229
Total Putouts          171,677      53.134

I’ve seen at least 2-3 triple plays that I can remember.  And I don’t think I remember any catcher interference (there was a play during the 1975 World Series between Carlton Fisk and Ed Armbrister, but that wasn’t catcher interference, or any interference officially for that matter).  But I think the key word is remember.  Catcher Interference just isn’t that memorable of a play I guess – or of course I just haven’t ever seen one.

Incidently, I included Total Putouts as a sanity check – something we can calculate in our heads.  3,231 games * 27 putouts * 2 teams = 174,474.  Pretty close to the actual number of 171,677.  In fact since the home team doesn’t always bat in the 9th inning, you would guesstimate something less than 174,474 as the result was.  Sanity checks like this are often left out of presented data, yet are critical in helping grok and feel comfortable with stats.

Wind impact on extreme home runs

Just reading through “The Physics of Baseball” by Adair.  He says “I expect the longest home runs hit in outdoor parks are always wind assisted”. Yes!!!  As I said here, I think Williams HR at Fenway was definitely wind assisted.

The Longest Home Run at Fenway Park

As any Red Sox fan will tell you, the Lone Red seat in the right field bleachers is exactly 503 ft from home plate.  It represents the landing spot of Ted Williams epic HR blast on June 9, 1946.  It was his second game of the afternoon BTW.

The only one to come close since then was Manny Ramirez on June 23, 2001.  He hit two mammoth shots that day – officially measuring in at 463 and 501 ft.

Below is radial plot showing the Maximum and Average wind speeds in mph per direction.  This is based on the the 3231 games played between 1970 and 2009.  To get an idea of the park’s orientation look here.

As a reminder, the plot is a “wind rose” which means based on the orientation of Fenway Park, 180 is blowing out to left and around 270 is blowing out to the short porch in right field (aka “Williamsburg” back in the day).

Based on historical weather data, I’ve added a point (“T”) to indicate the wind speed and direction on June 9, 1946.  The “M” indicates the wind at the time of Manny’s HR.  Clearly Ted’s HR was aided by a strong (15mph, at least) wind which blew from the West for the entire afternoon.  In the 40 years of data reviewed only one day had stronger wind conditions (May 13, 1979 – 3 HR’s hit in an 8-2 Red Sox win over the A’s).

Obviously, we’ll never know the exact distances and wind speeds.  But I present this as  evidence that Manny’s HR was far more impressive that Williams’.

Impact of weather at Fenway

From my thesis dataset which combines 40 years of games at Fenway Park with the weather at the start of the game. These plots were done using R’s radial.plot() in the plotrix package.

First is the number of games held “per Direction”. So we can see that the most common direction for winds at Fenway is from the Southwest at 200 degrees:

This actually has me a little bit worried. Though hard to tell from the graphic, the lowest number is 23 games at due North (360 degrees), but you can generally see that relatively few games are played with winds from the North-Northeast.

If we then take some baseball statistics like hits and divide by the above graphic we get this:

This seems to make sense:

  • More HR’s get hit when the wind is blow out – well duh
  • Interestingly, I’d expected the number of singles to be roughly equal for all directions, but there are those two spikes 20 and 40 degrees.  When the wind is blowing in do they take a break from swinging for the fences?
  • Could the builders of Fenway have oriented the park to take advantage of prevailing winds? I’ll have to do some research.

Growing up in New England, I’ve always equated “nor’easter” with a winter storm – they don’t play many games in the winter or during nor’easters. Still the dearth of games which actually have winds from the North bothers me.

UPDATE (3/27/2012):  In Glenn Stout’s book, “Fenway 1912”, he says the park was oriented to match the previously existing field at the site – Huntington Avenue Grounds. Also, rule 1.04 of MLB’s official rules states “it is desirable that the line from home base through the pitchers plate to second base shall run East-Northeast.”  According to, this is supposed to be so the setting sun shines in right field where fewer balls are hit.  So it seems to make sense that an older park like Fenway would be built to follow this rule.

UPDATE (3/30/2012):  Dr. Steve at CCSU Weather tells me that my wind rose looks exactly as it’s supposed to since the actual weather data I used was from the Logan Airport station where due to its position on the coast, it tends to only have either land or sea breezes. Also as I stated above, they don’t play many Sox games during nor’easters.  The weather between Fenway and Logan is probably not exactly the same, but I think they’ll be close enough AND I think they’ll be consistently different.  Still there is no weather station at Fenway, and the game time reports I’ve seen are over the place (literally, when compared to the weather at Logan) so if the conditions are not consistent between the two locations well then I’ll probably find no affects on runs scored.