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08-16-2008 02:08 PM #31
08-16-2008 04:01 PM #32
For an individual batter, when you add RS to RBI, the only thing counted twice is a home run, which goes under both.
When you subtract the number of home runs, you aren't taking all the runs from those home runs out, just one run from each, which was the batter driving himself in.
08-18-2008 11:49 AM #33
There is no other player involved in the run scored by the guy who hit the home run, so that run gets undervalued by the RP formula. To be a mathematically consistent tally of actual runs, the sum of runs scored and RBIs should be divided by two.
The "counted twice" argument for subtracting home runs is a mathematical fallacy. Tango's argument for subtracting home runs isn't to avoid counting the run twice; it's to make the output of the RP formula correlate more closely with the RC formula.
If you divide the sum of runs scored and RBIs by two for all of the players on a team and add up those values, you should get the actual runs scored by the team, less those runs for which no RBI is awarded (scored on DP or WP).
Once you accept that there's no mathematical justification for subtracting home runs, then the test becomes whether the results provide a valid measure of the run scoring value of a hitter. Tango's test is that the results are close to those obtained by using RC. Tango also proposes additional adjustments beyond subtracting out home runs to make the results correlae even more closely with RC.
12-08-2008 10:18 AM #34
Beyond the Box Score has a post up introducing what they call JustVORP (presumably named after the guy who designed it, whose name is Justin), which aims to correct some of the problems with VORP.
It's pretty interesting - I didn't realize the strange way that replacement level is calculated in regular VORP. The level is set by taking a percentage of the average offensive production at each position, which is an unfortunate choice because DHs on average hit worse than 1B-men, making it seem as if DH is a more difficult defensive position.
The JustVORP stat uses the defensive spectrum of DH-1B-....-SS-CA, and the associated adjustments. Also, it claims to correct for both park and league differences.
I'm not sure what correcting for league differences means. Judging by the results, it sounds like they established a separate replacement level for each league, which is lower in the NL. I say this because the top of the rankings are full of NL players. There are only three AL players in the overall top 10, and that's if you count Manny Ramirez (not sure how they dealt with him).
Also, the list shines pretty favorably on a couple of Orioles - here is the top of the AL rankings (not including Ramirez/Teixeira, who scored 68/53 respectively):
1. Sizemore - 66
2. A-Rod - 62
3. Mauer - 54
4. Pedroia - 53
5. Roberts - 52
5. Markakis - 52
12-08-2008 01:04 PM #35
Replacement level players are cheap, so the skill level of replacement players ought to be similar for either league. The only way that they would be significantly different would be if one league had substantially superior farm systems than the other league.
However, in reading more carefully, I do see that they've defined replacement level differently for each league, 73 percent vs 78 percent. I think that means that they've normalized replacement level to correspond to the average performance level of each league, but I'm not completely sure. In other words, "replacement level" is approximately equal for either league, but that value of performance corresponds to 73 percent of average offensive production in the stronger American League and 78 percent of average offensive production in the weaker National League.
NL pitchers don't have to face the DH, except for interleague games, so the NL pitchers ought to post higher strikeout rates, lower walk rates, lower WHIP, and lower ERAs -- on average. This would tend to depress the average number of runs scored and driven in by NL hitters.
The other factor which affects the level of ability in the 2 leagues is the disparity in team payrolls. We know that payrolls correlate somewhat weakly with actual production, but there is a correlation, and that correlation increases when taken over the entire group of players in a league, instead of just a single team. The average payroll in the AL was over $13 million higher than the average NL payroll in 2008, and that payroll disparity naturally equates to slightly stronger teams in the junior circuit. This means that the average 5th starter on an AL team will likely be a little better than the average 5th starter on an NL team, and likewise for the hitters at the bottom end of the batting order and on the bench.
02-18-2009 10:41 PM #36
Is there a place to get statistics on what the league average player at each position would look like? (i.e. league average CF had an avg of ... HR of ...)
Thanks in advance.
12-30-2009 07:01 PM #37
01-13-2010 07:31 PM #38
01-13-2010 11:40 PM #39
01-14-2010 12:25 AM #40
01-14-2010 09:03 AM #41
01-22-2010 05:28 PM #42
03-10-2013 08:48 PM #43
Is there a way to find league average wOBA by position per year?
Thanks in advance.
03-11-2013 07:46 AM #44
03-11-2013 02:50 PM #45