{"id":923,"date":"2020-10-07T08:47:40","date_gmt":"2020-10-07T15:47:40","guid":{"rendered":"http:\/\/www.mfooz.com\/bblog\/?p=923"},"modified":"2020-10-07T08:47:40","modified_gmt":"2020-10-07T15:47:40","slug":"xr-prediction","status":"publish","type":"post","link":"https:\/\/www.mfooz.com\/bblog\/?p=923","title":{"rendered":"XR Prediction"},"content":{"rendered":"<p>The initial goal was to predict XR values for pitchers prior to the cards coming out. So I used MLB 2019 stats and ABL 2020 XR values (all parks). Got ERA, xFIP, &amp; SIERA from Fangraphs. Correlations were fair, around 0.7. Best was xFIP at 0.71 for starters.<\/p>\n<p>Finally found some linear weights at <a href=\"https:\/\/baseballsavant.mlb.com\/\">Baseball Savant<\/a>, namely wOBA. This provided a much better correlation. (Also tried xwOBA, but it was worse.) Used a list of exclusive starters and exclusive shorts. They were fairly different, with shorts having worse correlation. I&#8217;m guessing that&#8217;s a combination of smaller sample size and deviation from average platoon rates. Did not try longs, closers, or combos. The pitcher estimate equations:<\/p>\n<pre>STARTER:  XR = 824 * wOBA - 103     R=0.88\n  SHORT:  XR = 601 * wOBA -  33     R=0.80\n<\/pre>\n<p>If I ever had to choose keeps without cards, I would get data for all qualified pitchers, then sort them into categories, when appropriate.<\/p>\n<p>Did batters too. Unsurprisingly, correlation to wOBA was even better. (xwOBA was again worse.) For batters:<\/p>\n<pre>      XR =  736 * wOBA - 138    R=0.86\n<\/pre>\n<p>Take-aways:<\/p>\n<ul>\n<li>TPB pitcher ratings correlate with linear weights, as opposed to, say, ERA.<\/li>\n<li>I could get reasonable XR estimates for both batters and pitchers if I didn&#8217;t have access to the cards.<\/li>\n<\/ul>\n<p>The spreadsheet with the data is named <tt>ABL Predictions<\/tt>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The initial goal was to predict XR values for pitchers prior to the cards coming out. So I used MLB 2019 stats and ABL 2020 XR values (all parks). Got ERA, xFIP, &amp; SIERA from Fangraphs. Correlations were fair, around 0.7. Best was xFIP at 0.71 for starters. Finally found some linear weights at Baseball &hellip; <a href=\"https:\/\/www.mfooz.com\/bblog\/?p=923\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">XR Prediction<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,12,3],"tags":[],"class_list":["post-923","post","type-post","status-publish","format-standard","hentry","category-abl","category-tabletop-baseball","category-triple-play-baseball"],"_links":{"self":[{"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=\/wp\/v2\/posts\/923","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=923"}],"version-history":[{"count":1,"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=\/wp\/v2\/posts\/923\/revisions"}],"predecessor-version":[{"id":925,"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=\/wp\/v2\/posts\/923\/revisions\/925"}],"wp:attachment":[{"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=923"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=923"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mfooz.com\/bblog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=923"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}