Comments on: 39+ Games As DH With WPA >= .15 http://www.baseball-reference.com/blog/archives/9640 This and that about baseball stats. Tue, 16 Jul 2013 17:01:55 +0000 hourly 1 https://wordpress.org/?v=4.6 By: Johnny Twisto http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81961 Wed, 12 Jan 2011 19:56:41 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81961 David, I guess I'm confused as well. I thought rPos was derived from measuring fielding differences between positions, but you're right, that would not explain why pitchers have such a high rPos (I had never noticed that before).

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By: 39+ Games As DH With WPA >= .15 » Baseball-Reference Blog » Blog … | Baseball News and Events http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81867 Wed, 12 Jan 2011 14:57:15 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81867 [...] more from the original source: 39+ Games As DH With WPA >= .15 » Baseball-Reference Blog » Blog … Posted in General Tags: david, games, kevin-bryant, mentioned-on-twitter, reference, twitter, [...]

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By: DavidRF http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81854 Wed, 12 Jan 2011 12:30:16 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81854 @18
"David, you misunderstood Kds. I am pretty sure B-R WAR does use defensive performance to set the differences between positions, by looking at the ratings of everyone who plays multiple positions in a season."
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I guess I'm still confused then. I thought Rpos was an adjustment based the difference in offensive replacement level due to positional scarcity. As you say, its the extra fielding skill required by the defensive positions that creates that scarcity, but the number itself is obtained by measuring offense, not measuring defense.

Pitchers have a high value of rPos. Per plate appearance, its enormous. That number is not because of their fielding. Its because they can't hit.

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By: mccombe35 http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81804 Wed, 12 Jan 2011 04:34:39 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81804 Interesting list.

Guys like Ortiz & Hafner are way up there because they hardly ever played the field.

Less than 250 games in the field between them. Too bad Thomas & Baines (Over 2,000 games in the field combined) will/are lumped into that DH group when being looked at historically...

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By: Johnny Twisto http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81802 Wed, 12 Jan 2011 04:17:28 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81802 David, you misunderstood Kds. I am pretty sure B-R WAR does use defensive performance to set the differences between positions, by looking at the ratings of everyone who plays multiple positions in a season.

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By: DavidRF http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81799 Wed, 12 Jan 2011 04:15:08 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81799 Ah... thanks. I can see significant shifts in rPos for Eddie Collins (2B) between 1919 and 1920 and Stan Hack (3B) between 1939 and 1940. Those two positions were indeed trading places in the defensive spectrum during the few decades but its interesting to see the sharp breaks in the positional adjustment at the end of these particular decades. I don't have the raw data, but at some point they might consider smoothing those transitions.

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By: kds http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81796 Wed, 12 Jan 2011 03:28:08 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81796 If I remember correctly, Rpos is recomputed for each decade. With some players you can see this when their Rpos changes between year xyz9 and the next year. (remember that Rpos, like Rrep depends upon playing time.)

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By: DavidRF http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81789 Wed, 12 Jan 2011 02:04:44 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81789 @13
Good point on Rpos and bunching of talent at positions (e.g. 1950s CF).

Spot-checking 1950s data, they don't appear to be making the big mistakes that you are worried about. For example, in the 1955 NL, the highest offense position was CF thanks to Mays & Snider (and Ashburn & Bell). But they still give a higher Rpos to CF than they do LF-RF-1B. I don't know if they do that by checking the replacement level (i.e. ignoring the stars) or doing multi-year averages or a sanity check for obvious defensive spectrum ordering or combinations of the above. Anyone know where to find algorithmic details?

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By: Bastaducci http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81779 Wed, 12 Jan 2011 00:29:41 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81779 Defensive war really is useless. I seen a post on her where it had Doug Flynn as a bad defensive player. that is all I need to know about defensive war. I mean I do respect that they are trying to put a number on defense and hopefully somehow they can improve it and make it worth looking at. but as of now it has no relevance.

Now offensive WAR I love although it too needs to be tinkered with. right now WAR has hitters a little high and Pitchers a little low. take the yankees last year..I love Cano but there is no way he was worth more to the Yanks than Sabathia.

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By: kds http://www.baseball-reference.com/blog/archives/9640/comment-page-1#comment-81756 Tue, 11 Jan 2011 21:40:07 +0000 http://www.baseball-reference.com/blog/?p=9640#comment-81756 The position adjustment does not come from offense and sould not be measured by offense. For some years in '50's CF's (Willie, Mickey and the Duke), hit better than RF. But it would have been absurd to give a better Rpos to RF. Very few of the RF could have played acceptable CF. All of the CF's would have been good in right. Suppose you took 1000 players who could at least field well enough to play 1B. Maybe 100 of them could field well enough to play SS. The SS would be better fielders at first than the IBmen, and the IB's would be much worse at SS. We measure the defensive difference to get Rpos. Because there are 1000 choices in the 1B group and only 100 of those in the SS group, we expect the 1B group to hit better, at the top and on average. That is positional scarcity. In practice the difference in offense, measured in runs, should be about the same as the difference in defense, so it can be used as an approximation, but the difference in defense is what matters. One would expect them to be close, otherwise the market is inefficient and GM's are making lousy decisions.

For various technical reasons we often measure offense from average, but we could measure it from zero. So that a sum of the individuals would approximate the actual team runs scored. We can say that a good batter adds 100 runs to his teams offense, an average one 80, and a poor hitter 60. We have no way of doing this for defense. (Aside from the question; is it pitching or defense?) A SS fields a lot more balls than a 1B, and most of what a 1B does, catch throws, any other player at that level could do as well. So a SS is clearly worth more on defense than a 1B. Even a very bad SS and a very good 1B. Rpos is our best estimate of the average difference in defensive worth among the positions. (Including DH, another headache, but this post is too long already!)

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