by YountFan » Fri Mar 17, 2006 10:28 pm
Almost all Hitter and Pitchers have 10 > symbols on their cards (5 on a side). That means the BP single effect can happen 10/216 (5%) of the time. In a park like Tiger this 5% is nearly always an out because you only have a 5 or 10% chance of it being a hit. In Royals 80% of that 5% will result in hits. It seems small but over a season it adds up.
Figure 5500 AB/season * 5% = 275 AB. In Tiger 5% of those are hits (13 hits), and Royals 80% (220 hits). This mean 1.4 hits per player at Tiger on average and a lower BA, and 24 hits per player in Royals. Of couse this assumes all 12 ballparks are Royal and Tigers, but you can cut the number in half to see the home park effect.
Consider a lefty with 600 AB and a .250 hitter in a league where all park have a BP rating of 0. He would have 150 hits.
Put him in Tiger and add 600 * .05 * .1 = 3 hits. 153/600 = .255
Put him in Royals and add 600 * .05 * .8 = 24 hits 174/600 = .290
There is a reason the Royal's team have high averages. The same works for BP HR (#), but it that are not as evenly distributed.
The above example has some very broad assumptions, but is correct in theory. So Tiger good for pitchers bad for hitters