tag:blogger.com,1999:blog-608528753722196209.post9218027551983623408..comments2015-07-30T13:44:51.403-07:00Comments on Cybermetrics: How Well Do OPS And wOBA Predict Team Runs?Cyril Moronghttp://www.blogger.com/profile/07148864847009186694noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-608528753722196209.post-52093365001085320882013-07-31T21:31:11.251-07:002013-07-31T21:31:11.251-07:00So, 165-135. Hmmm, let me see ... the SD of that ...So, 165-135. Hmmm, let me see ... the SD of that is 8.6 games, so that's a bit less than 2 SD difference.<br /><br />More significant than I thought!Phil Birnbaumhttp://www.blogger.com/profile/03800617749001032996noreply@blogger.comtag:blogger.com,1999:blog-608528753722196209.post-55784116662303335102013-07-31T13:57:22.345-07:002013-07-31T13:57:22.345-07:00OPS was closer in 165 cases. But in around 260 cas...OPS was closer in 165 cases. But in around 260 cases OPS and wOBA are within .10 runs per game of each other. In about 160 cases they are with .05 of each otherCyril Moronghttp://www.blogger.com/profile/07148864847009186694noreply@blogger.comtag:blogger.com,1999:blog-608528753722196209.post-54794007131229600452013-07-31T13:10:27.783-07:002013-07-31T13:10:27.783-07:00My guess is that OPS will predict just a bit bette...My guess is that OPS will predict just a bit better because the standard error of the regression is just a bit lower. If I get a chance, I will try what you sayCyril Moronghttp://www.blogger.com/profile/07148864847009186694noreply@blogger.comtag:blogger.com,1999:blog-608528753722196209.post-85498302410639344742013-07-31T11:29:47.069-07:002013-07-31T11:29:47.069-07:00A large SD would tell us that there's lots of ...A large SD would tell us that there's lots of randomness involved, so it's hard to tell the difference between the two stats with a sample size that small.<br /><br />Or, what if you do this? For each season, see which of the two regression equations predicts team runs better for that year. Maybe wOBA will go 160-140, or something.<br /><br />Phil Birnbaumhttp://www.blogger.com/profile/03800617749001032996noreply@blogger.comtag:blogger.com,1999:blog-608528753722196209.post-27269985089814541572013-07-31T10:11:18.095-07:002013-07-31T10:11:18.095-07:00There probably is a way to get a standard error fo...There probably is a way to get a standard error for the correlation coefficient. I think I would have to look in one of my stats textbooks.<br /><br />If I did those 10 years separately like you say and got the result you suggest, what would it tell us?Cyril Moronghttp://www.blogger.com/profile/07148864847009186694noreply@blogger.comtag:blogger.com,1999:blog-608528753722196209.post-18736341022630138332013-07-31T09:31:41.851-07:002013-07-31T09:31:41.851-07:00Is there a way to get a standard error for the cor...Is there a way to get a standard error for the correlation coefficient?<br /><br />What if you do each year separately, take the 10 coefficients, and calculate the SD of those. Then, the overall coefficient's SD is 1/3 that size, right? I bet that SD is large compared to the difference between .95584 and .95297.<br /><br />Just a guess.Phil Birnbaumhttp://www.blogger.com/profile/03800617749001032996noreply@blogger.comtag:blogger.com,1999:blog-608528753722196209.post-42784684735692661312013-07-30T09:01:24.609-07:002013-07-30T09:01:24.609-07:00I used the years 2003-2012. So that is 300 team se...I used the years 2003-2012. So that is 300 team seasons. Here are the correlations between each stat and team runs per game:<br /><br />OPS: 0.95584<br />wOBA: 0.952973<br />1.8*OBP + SLG: 0.95714<br /><br />So 1.8*OBP + SLG is better than wOBA. Not what I expected.<br />Cyril Moronghttp://www.blogger.com/profile/07148864847009186694noreply@blogger.comtag:blogger.com,1999:blog-608528753722196209.post-49243248429707130632013-07-30T05:59:14.509-07:002013-07-30T05:59:14.509-07:00I think that is why I looked at 2007-2009 and got ...I think that is why I looked at 2007-2009 and got the same results. So I did 180 team/seasons. But maybe more should be looked atCyril Moronghttp://www.blogger.com/profile/07148864847009186694noreply@blogger.comtag:blogger.com,1999:blog-608528753722196209.post-66214164186117881682013-07-29T21:19:48.455-07:002013-07-29T21:19:48.455-07:00Maybe it's just random? 90 seasons isn't ...Maybe it's just random? 90 seasons isn't a whole lot, and OPS is pretty good, almost as good as wOBA.Phil Birnbaumhttp://www.blogger.com/profile/03800617749001032996noreply@blogger.com