Two Pitcher xBABIPS
Thanks to two excellent researchers, we have two different pitcher xBABIPs nestled within the posts on this site.
Matt Swartz has an xBABIP that’s part of SIERA. He was nice enough to re-run it with all pitchers with 40 innings pitched or more for 2003-12. He did not adjust for usage by weighting pitchers with high IP more heavily, but he did regress BABIP using factors that his research has shown to influence the number. His pitcher xBABIP formula is:
BABIP = .290 + .045*GB% – .103*K%.
Steve Staude used batted ball data to find a pitcher xBABIP in the Community Blog a while back. Of course, the weakness of a model using line drive percentage is the fickleness of that stat from stadium to stadium and year to year, but it does make a lot of sense intuitively: give up fewer frozen ropes and you’ll give up fewer hits. His regression led him to the following pitcher xBABIP formula:
xBABIP = 0.4*LD% – 0.6*FB%*IFFB% + 0.235
To help out the fantasy player looking at pitchers for 2013, I put all pitchers with more than 100 innings pitched on one leaderboard featuring their BABIP and both xBABIPs. I sorted by the difference between their Line Drive xBABIP and their SIERA xBABIP.
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| Name | GB% | FB% | IFFB% | LD% | BABIP | SIERA BABIP | LD BABIP | DELTA |
|---|---|---|---|---|---|---|---|---|
| Chris Young | 22.3% | 58.2% | 15.3% | 19.5% | 0.287 | 0.2833 | 0.2596 | -0.0238 |
| Ross Detwiler | 50.8% | 32.8% | 9.6% | 16.4% | 0.263 | 0.2971 | 0.2817 | -0.0154 |
| Phil Hughes | 32.4% | 47.6% | 15.6% | 19.9% | 0.286 | 0.2837 | 0.2700 | -0.0136 |
| Bartolo Colon | 45.7% | 36.3% | 11.3% | 18.0% | 0.286 | 0.2958 | 0.2824 | -0.0134 |
| Marco Estrada | 34.3% | 45.4% | 18.0% | 20.3% | 0.298 | 0.2793 | 0.2672 | -0.0121 |
| Derek Holland | 43.1% | 40.1% | 10.5% | 16.8% | 0.261 | 0.2889 | 0.2769 | -0.0120 |
| Aaron Laffey | 49.8% | 31.2% | 11.5% | 18.9% | 0.258 | 0.3009 | 0.2891 | -0.0118 |
| Trevor Cahill | 61.2% | 22.7% | 9.2% | 16.1% | 0.289 | 0.2984 | 0.2869 | -0.0115 |
| Barry Zito | 40.4% | 39.6% | 13.4% | 20.0% | 0.281 | 0.2935 | 0.2832 | -0.0103 |
| Bruce Chen | 32.7% | 44.8% | 17.6% | 22.4% | 0.304 | 0.2873 | 0.2773 | -0.0100 |
| Hector Noesi | 37.0% | 45.3% | 9.2% | 17.8% | 0.266 | 0.2912 | 0.2812 | -0.0100 |
| Jordan Lyles | 53.9% | 29.0% | 8.8% | 17.1% | 0.301 | 0.2980 | 0.2881 | -0.0099 |
| Jeff Francis | 50.3% | 31.0% | 12.0% | 18.8% | 0.341 | 0.2971 | 0.2879 | -0.0092 |
| Gavin Floyd | 47.2% | 34.7% | 12.2% | 18.1% | 0.299 | 0.2907 | 0.2820 | -0.0087 |
| Henderson Alvarez | 57.0% | 24.3% | 8.1% | 18.7% | 0.291 | 0.3056 | 0.2980 | -0.0076 |
| Colby Lewis | 33.0% | 45.8% | 16.1% | 21.2% | 0.279 | 0.2824 | 0.2756 | -0.0068 |
| Jason Vargas | 40.2% | 40.5% | 11.3% | 19.4% | 0.254 | 0.2917 | 0.2851 | -0.0066 |
| Tommy Hunter | 45.4% | 34.6% | 12.0% | 20.0% | 0.298 | 0.2966 | 0.2901 | -0.0065 |
| Matt Moore | 37.4% | 42.9% | 14.3% | 19.6% | 0.293 | 0.2830 | 0.2766 | -0.0064 |
| J.A. Happ | 44.0% | 38.9% | 10.1% | 17.1% | 0.315 | 0.2861 | 0.2798 | -0.0063 |
| Travis Blackley | 47.7% | 34.7% | 7.8% | 17.5% | 0.268 | 0.2950 | 0.2888 | -0.0062 |
| Kyle Kendrick | 46.5% | 35.8% | 8.5% | 17.7% | 0.278 | 0.2932 | 0.2875 | -0.0057 |
| Ryan Vogelsong | 43.5% | 38.0% | 11.1% | 18.5% | 0.284 | 0.2889 | 0.2837 | -0.0052 |
| Hiroki Kuroda | 52.3% | 29.5% | 10.4% | 18.2% | 0.281 | 0.2943 | 0.2894 | -0.0049 |
| Blake Beavan | 36.6% | 41.7% | 12.3% | 21.8% | 0.282 | 0.2957 | 0.2914 | -0.0042 |
| Cliff Lee | 45.0% | 36.9% | 11.8% | 18.1% | 0.309 | 0.2851 | 0.2813 | -0.0038 |
| Jake Peavy | 36.5% | 44.6% | 11.2% | 18.9% | 0.272 | 0.2838 | 0.2806 | -0.0031 |
| Clayton Richard | 53.8% | 27.8% | 5.8% | 18.4% | 0.272 | 0.3021 | 0.2989 | -0.0031 |
| Aaron Harang | 38.6% | 41.0% | 12.1% | 20.5% | 0.277 | 0.2902 | 0.2872 | -0.0029 |
| Brian Duensing | 47.3% | 32.7% | 10.7% | 20.0% | 0.319 | 0.2962 | 0.2940 | -0.0022 |
| Matt Harrison | 49.0% | 30.9% | 11.0% | 20.1% | 0.284 | 0.2964 | 0.2950 | -0.0014 |
| Chris Capuano | 40.3% | 39.1% | 12.9% | 20.5% | 0.284 | 0.2877 | 0.2867 | -0.0010 |
| Johan Santana | 33.1% | 42.9% | 19.3% | 24.0% | 0.301 | 0.2820 | 0.2813 | -0.0007 |
| Derek Lowe | 59.2% | 21.0% | 5.5% | 19.8% | 0.326 | 0.3078 | 0.3073 | -0.0005 |
| Ervin Santana | 43.2% | 37.3% | 9.7% | 19.5% | 0.241 | 0.2915 | 0.2913 | -0.0002 |
| Jerome Williams | 53.6% | 28.2% | 6.6% | 18.2% | 0.293 | 0.2965 | 0.2966 | 0.0001 |
| Brandon Morrow | 41.1% | 39.9% | 10.1% | 19.0% | 0.252 | 0.2865 | 0.2868 | 0.0004 |
| Josh Beckett | 42.5% | 36.7% | 12.4% | 20.8% | 0.294 | 0.2905 | 0.2909 | 0.0004 |
| Mat Latos | 45.6% | 36.1% | 9.0% | 18.4% | 0.266 | 0.2883 | 0.2891 | 0.0008 |
| Clayton Kershaw | 46.9% | 34.0% | 12.2% | 19.1% | 0.262 | 0.2849 | 0.2865 | 0.0016 |
| Kevin Millwood | 44.7% | 33.5% | 12.9% | 21.8% | 0.304 | 0.2942 | 0.2963 | 0.0021 |
| Dan Haren | 39.6% | 39.6% | 11.5% | 20.7% | 0.302 | 0.2883 | 0.2905 | 0.0022 |
| Luis Mendoza | 52.1% | 27.1% | 10.6% | 20.8% | 0.31 | 0.2983 | 0.3010 | 0.0027 |
| R.A. Dickey | 46.1% | 34.1% | 12.7% | 19.8% | 0.275 | 0.2852 | 0.2882 | 0.0030 |
| Kevin Correia | 51.2% | 29.1% | 5.4% | 19.6% | 0.274 | 0.3005 | 0.3040 | 0.0035 |
| Bronson Arroyo | 41.4% | 37.5% | 10.2% | 21.1% | 0.286 | 0.2927 | 0.2965 | 0.0038 |
| A.J. Burnett | 56.9% | 24.3% | 8.5% | 18.8% | 0.294 | 0.2938 | 0.2978 | 0.0040 |
| Jeremy Hellickson | 41.8% | 37.2% | 10.4% | 21.0% | 0.261 | 0.2916 | 0.2958 | 0.0042 |
| Kris Medlen | 53.4% | 28.2% | 8.6% | 18.5% | 0.261 | 0.2902 | 0.2944 | 0.0042 |
| Madison Bumgarner | 47.9% | 33.3% | 8.7% | 18.8% | 0.276 | 0.2884 | 0.2928 | 0.0044 |
| Justin Masterson | 55.7% | 25.0% | 7.0% | 19.3% | 0.309 | 0.2969 | 0.3017 | 0.0048 |
| Carlos Villanueva | 36.7% | 44.0% | 9.3% | 19.2% | 0.275 | 0.2824 | 0.2872 | 0.0048 |
| Tim Hudson | 55.5% | 25.2% | 4.1% | 19.3% | 0.27 | 0.3010 | 0.3060 | 0.0050 |
| Edwin Jackson | 47.3% | 35.8% | 3.6% | 16.8% | 0.278 | 0.2893 | 0.2945 | 0.0051 |
| Wei-Yin Chen | 37.1% | 42.1% | 10.1% | 20.8% | 0.274 | 0.2873 | 0.2927 | 0.0054 |
| Ricky Romero | 53.5% | 26.4% | 7.2% | 20.1% | 0.311 | 0.2986 | 0.3040 | 0.0054 |
| Jon Lester | 49.2% | 28.8% | 14.4% | 22.0% | 0.312 | 0.2926 | 0.2981 | 0.0055 |
| Alex Cobb | 58.8% | 21.2% | 9.3% | 20.0% | 0.295 | 0.2973 | 0.3032 | 0.0059 |
| Mike Minor | 35.4% | 43.7% | 10.4% | 20.9% | 0.252 | 0.2854 | 0.2913 | 0.0059 |
| Jake Westbrook | 58.1% | 21.0% | 8.3% | 20.8% | 0.312 | 0.3016 | 0.3077 | 0.0061 |
| Wandy Rodriguez | 48.0% | 31.6% | 8.2% | 20.5% | 0.28 | 0.2952 | 0.3015 | 0.0062 |
| Joe Saunders | 43.1% | 35.6% | 9.2% | 21.3% | 0.305 | 0.2939 | 0.3005 | 0.0066 |
| Ian Kennedy | 37.3% | 42.1% | 10.0% | 20.6% | 0.306 | 0.2854 | 0.2921 | 0.0068 |
| Lucas Harrell | 57.2% | 22.5% | 8.2% | 20.3% | 0.289 | 0.2983 | 0.3051 | 0.0068 |
| Carlos Zambrano | 49.1% | 28.3% | 13.3% | 22.6% | 0.284 | 0.2955 | 0.3028 | 0.0073 |
| Josh Tomlin | 41.6% | 37.2% | 7.4% | 21.2% | 0.309 | 0.2959 | 0.3033 | 0.0073 |
| Dillon Gee | 50.3% | 29.6% | 9.6% | 20.1% | 0.301 | 0.2910 | 0.2984 | 0.0073 |
| Matt Cain | 37.4% | 41.7% | 10.8% | 20.9% | 0.259 | 0.2842 | 0.2916 | 0.0074 |
| James Shields | 52.3% | 29.0% | 7.5% | 18.7% | 0.292 | 0.2892 | 0.2968 | 0.0075 |
| Zach McAllister | 40.5% | 40.3% | 7.0% | 19.2% | 0.304 | 0.2873 | 0.2949 | 0.0076 |
| Justin Verlander | 42.3% | 35.6% | 15.4% | 22.2% | 0.273 | 0.2833 | 0.2909 | 0.0076 |
| Matt Garza | 47.3% | 33.2% | 8.7% | 19.5% | 0.271 | 0.2880 | 0.2957 | 0.0077 |
| Homer Bailey | 44.9% | 35.4% | 7.1% | 19.7% | 0.29 | 0.2904 | 0.2987 | 0.0083 |
| League Average | 45.1% | 34.0% | 10.0% | 20.9% | 0.297 | 0.2899 | 0.2982 | 0.0083 |
| Jon Niese | 48.3% | 30.7% | 10.3% | 21.0% | 0.272 | 0.2914 | 0.3000 | 0.0086 |
| Jered Weaver | 36.0% | 42.8% | 9.4% | 21.1% | 0.241 | 0.2864 | 0.2953 | 0.0088 |
| C.J. Wilson | 50.3% | 29.9% | 7.4% | 19.9% | 0.281 | 0.2920 | 0.3013 | 0.0093 |
| Ricky Nolasco | 46.6% | 31.7% | 8.6% | 21.6% | 0.309 | 0.2955 | 0.3050 | 0.0095 |
| Clay Buchholz | 47.6% | 32.9% | 4.2% | 19.5% | 0.283 | 0.2948 | 0.3047 | 0.0099 |
| Miguel Gonzalez | 34.9% | 42.6% | 10.5% | 22.4% | 0.26 | 0.2875 | 0.2978 | 0.0103 |
| Jaime Garcia | 53.7% | 25.9% | 7.2% | 20.3% | 0.339 | 0.2946 | 0.3050 | 0.0104 |
| Chris Volstad | 49.2% | 28.1% | 9.2% | 22.7% | 0.315 | 0.2998 | 0.3103 | 0.0105 |
| Rick Porcello | 53.2% | 22.6% | 15.8% | 24.2% | 0.344 | 0.2998 | 0.3104 | 0.0105 |
| David Price | 53.1% | 27.0% | 9.2% | 19.9% | 0.285 | 0.2887 | 0.2997 | 0.0110 |
| Jose Quintana | 47.2% | 31.1% | 7.5% | 21.7% | 0.299 | 0.2965 | 0.3078 | 0.0113 |
| Anibal Sanchez | 46.4% | 32.1% | 10.2% | 21.5% | 0.31 | 0.2899 | 0.3014 | 0.0115 |
| Jeremy Guthrie | 40.8% | 36.1% | 9.5% | 23.1% | 0.294 | 0.2952 | 0.3068 | 0.0116 |
| Johnny Cueto | 48.9% | 29.4% | 10.1% | 21.7% | 0.296 | 0.2923 | 0.3040 | 0.0117 |
| Scott Diamond | 53.4% | 25.6% | 4.0% | 21.0% | 0.292 | 0.3011 | 0.3129 | 0.0118 |
| Freddy Garcia | 40.2% | 34.8% | 16.7% | 25.0% | 0.297 | 0.2882 | 0.3001 | 0.0119 |
| Cole Hamels | 43.4% | 35.1% | 11.9% | 21.5% | 0.29 | 0.2839 | 0.2959 | 0.0121 |
| Paul Maholm | 51.2% | 27.5% | 7.7% | 21.3% | 0.281 | 0.2947 | 0.3075 | 0.0128 |
| Tommy Hanson | 39.8% | 39.4% | 8.0% | 20.7% | 0.314 | 0.2861 | 0.2989 | 0.0128 |
| Travis Wood | 34.3% | 43.9% | 8.6% | 21.8% | 0.244 | 0.2866 | 0.2995 | 0.0130 |
| Bud Norris | 39.2% | 39.6% | 9.4% | 21.2% | 0.301 | 0.2845 | 0.2975 | 0.0130 |
| CC Sabathia | 48.2% | 30.7% | 10.2% | 21.1% | 0.288 | 0.2873 | 0.3006 | 0.0133 |
| Jason Marquis | 52.5% | 26.7% | 4.5% | 20.7% | 0.307 | 0.2969 | 0.3106 | 0.0137 |
| Hisashi Iwakuma | 52.2% | 27.3% | 6.0% | 20.5% | 0.282 | 0.2934 | 0.3072 | 0.0138 |
| Jason Hammel | 53.2% | 28.1% | 3.2% | 18.7% | 0.291 | 0.2904 | 0.3044 | 0.0141 |
| Luke Hochevar | 43.3% | 35.0% | 8.0% | 21.7% | 0.315 | 0.2909 | 0.3050 | 0.0141 |
| Joe Kelly | 51.7% | 27.5% | 4.4% | 20.8% | 0.306 | 0.2964 | 0.3109 | 0.0146 |
| Doug Fister | 51.0% | 26.7% | 10.9% | 22.3% | 0.296 | 0.2919 | 0.3067 | 0.0148 |
| Ryan Dempster | 43.5% | 35.7% | 7.3% | 20.8% | 0.277 | 0.2876 | 0.3026 | 0.0149 |
| Edinson Volquez | 50.6% | 28.2% | 8.5% | 21.2% | 0.292 | 0.2904 | 0.3054 | 0.0150 |
| Mark Buehrle | 41.3% | 36.3% | 7.4% | 22.4% | 0.27 | 0.2930 | 0.3085 | 0.0155 |
| Tommy Milone | 38.1% | 37.3% | 12.9% | 24.7% | 0.31 | 0.2893 | 0.3049 | 0.0156 |
| Nathan Eovaldi | 45.5% | 31.3% | 8.9% | 23.2% | 0.317 | 0.2952 | 0.3111 | 0.0159 |
| Roy Halladay | 44.7% | 32.3% | 11.3% | 23.0% | 0.301 | 0.2891 | 0.3051 | 0.0160 |
| Randy Wolf | 42.9% | 34.2% | 7.9% | 22.9% | 0.337 | 0.2940 | 0.3104 | 0.0164 |
| Philip Humber | 34.9% | 42.9% | 7.9% | 22.2% | 0.294 | 0.2868 | 0.3035 | 0.0167 |
| Zack Greinke | 49.2% | 29.1% | 9.1% | 21.7% | 0.306 | 0.2885 | 0.3059 | 0.0175 |
| Yu Darvish | 46.2% | 31.6% | 12.3% | 22.2% | 0.295 | 0.2829 | 0.3005 | 0.0176 |
| Ubaldo Jimenez | 38.4% | 38.2% | 9.5% | 23.4% | 0.309 | 0.2889 | 0.3068 | 0.0179 |
| Kyle Lohse | 40.5% | 35.6% | 9.9% | 23.9% | 0.262 | 0.2911 | 0.3095 | 0.0183 |
| Brandon McCarthy | 40.5% | 35.1% | 10.5% | 24.4% | 0.295 | 0.2922 | 0.3105 | 0.0183 |
| Jordan Zimmermann | 43.4% | 33.4% | 9.7% | 23.2% | 0.288 | 0.2900 | 0.3084 | 0.0184 |
| Chris Sale | 44.9% | 32.0% | 12.2% | 23.0% | 0.294 | 0.2846 | 0.3036 | 0.0190 |
| Chad Billingsley | 45.4% | 33.1% | 6.1% | 21.5% | 0.308 | 0.2896 | 0.3089 | 0.0193 |
| Shaun Marcum | 35.4% | 41.5% | 9.3% | 23.1% | 0.28 | 0.2846 | 0.3042 | 0.0196 |
| Felix Hernandez | 48.9% | 28.6% | 10.4% | 22.5% | 0.308 | 0.2875 | 0.3072 | 0.0197 |
| Scott Feldman | 42.2% | 31.9% | 14.7% | 25.9% | 0.318 | 0.2906 | 0.3105 | 0.0199 |
| Jake Arrieta | 43.8% | 32.4% | 11.8% | 23.8% | 0.32 | 0.2871 | 0.3073 | 0.0202 |
| Ivan Nova | 45.2% | 32.4% | 7.7% | 22.4% | 0.331 | 0.2892 | 0.3096 | 0.0204 |
| Max Scherzer | 36.5% | 41.5% | 10.6% | 22.1% | 0.333 | 0.2761 | 0.2970 | 0.0209 |
| Gio Gonzalez | 48.2% | 30.0% | 8.4% | 21.9% | 0.267 | 0.2857 | 0.3075 | 0.0217 |
| Vance Worley | 46.0% | 29.8% | 9.8% | 24.2% | 0.34 | 0.2921 | 0.3143 | 0.0222 |
| Patrick Corbin | 45.7% | 31.0% | 7.7% | 23.3% | 0.317 | 0.2911 | 0.3139 | 0.0228 |
| Wade Miley | 43.3% | 33.7% | 6.4% | 23.0% | 0.293 | 0.2912 | 0.3141 | 0.0229 |
| Mike Leake | 48.9% | 26.6% | 8.3% | 24.5% | 0.306 | 0.2962 | 0.3198 | 0.0235 |
| Yovani Gallardo | 47.7% | 31.5% | 4.0% | 20.9% | 0.29 | 0.2871 | 0.3110 | 0.0240 |
| Francisco Liriano | 43.8% | 34.8% | 5.4% | 21.3% | 0.3 | 0.2849 | 0.3089 | 0.0240 |
| James McDonald | 39.2% | 39.4% | 4.3% | 21.4% | 0.269 | 0.2858 | 0.3104 | 0.0246 |
| Joe Blanton | 44.6% | 32.0% | 7.4% | 23.4% | 0.31 | 0.2889 | 0.3144 | 0.0255 |
| Felix Doubront | 43.7% | 33.0% | 8.6% | 23.4% | 0.312 | 0.2854 | 0.3116 | 0.0262 |
| Adam Wainwright | 50.8% | 26.3% | 6.6% | 23.0% | 0.315 | 0.2901 | 0.3166 | 0.0265 |
| Josh Johnson | 46.2% | 30.2% | 7.2% | 23.6% | 0.302 | 0.2895 | 0.3164 | 0.0269 |
| Jarrod Parker | 44.3% | 30.1% | 10.6% | 25.6% | 0.29 | 0.2908 | 0.3183 | 0.0275 |
| Erik Bedard | 43.3% | 33.2% | 6.6% | 23.4% | 0.314 | 0.2876 | 0.3155 | 0.0278 |
| Stephen Strasburg | 44.2% | 33.1% | 9.2% | 22.7% | 0.311 | 0.2788 | 0.3075 | 0.0287 |
| Lance Lynn | 43.8% | 32.2% | 8.4% | 24.0% | 0.321 | 0.2848 | 0.3148 | 0.0300 |
| Jeff Samardzija | 44.6% | 33.1% | 3.8% | 22.3% | 0.296 | 0.2844 | 0.3167 | 0.0322 |
| Tim Lincecum | 45.9% | 30.3% | 3.8% | 23.8% | 0.309 | 0.2870 | 0.3233 | 0.0363 |
| Mike Fiers | 32.7% | 39.2% | 10.8% | 28.2% | 0.319 | 0.2789 | 0.3224 | 0.0435 |
You can download the full spreadsheet here if you like.
With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.
I love this. Thanks.
I play in a simulation league, where I suspect batted ball data are some of the main factors on how pitchers perform. I plan to use this to target pitchers who are likely to match or out-perform their conventional stats in simulation by comparing their LD BABIP to their actual BABIP.
My own attempt at finding xBABIP was (((GB-IFH) * SeasonalConstant1) + ((FB-HR-IFB) * SeasonalConstant2) + (LD * SeasonConstant3) + IFH +BUH) / (GB+FB+LD+BU-BUH)
The constants I grabbed from somewhere here are the hit rates: .159 for GB-IFH, .121 for OFFB, and .75 for LD (for 2012).
A sample:
Chris Young .2497
Ross Detwiler .2693
Phil Hughes .2819
Disclaimer: My file was created just before the end of the season and I can’t find where I grabbed the constants or the formula.
Cool, Eno, thanks for this. I have a second article waiting to be published that talks about the effects of IP on xBABIP’s accuracy, and a third in the works that has formulas more oriented towards future BABIP predictions. I just tweaked the second article to compare my formula and SIERA’s.
Regarding the fickleness of LD% from stadium to stadium — does anybody have an explanation of the causes of the differences in LD% from stadium to stadium? Colorado makes sense as to why it should be the highest, but why are Seattle and San Diego low but San Francisco high? I’m wondering if this has more to do with the interpretations of the individuals who are recording the batted ball types.
http://www.fangraphs.com/guts.aspx?type=pf&season=2011&teamid=0
Rally, I was tempted to use IFH as a factor in my formula, since it was obviously useful, but using it would have messed with what I was trying to accomplish (a defense-neutral BABIP estimator). If the goal is direct prediction of future BABIPs, though, it does seem like a good idea to consider IFH, assuming the pitcher’s defenders and fields are going to stay fairly consistent.
Depending on how high or low in a stadium each team has the stringer judging batted ball types may affect LD% because of how different heights can skew the perception of whether something had a high or low arc. This is the article I remember, which in the comments section raises as many questions as answers but is suggestive of one possible reason: http://www.hardballtimes.com/main/article/when-is-a-fly-ball-a-line-drive/
Thanks Will, interesting article. It does make a lot of sense that the distinction between a line drive and a fly ball would be harder to make from a higher vantage point. It might even help explain why fly ball pitchers tend to be shown giving up more line drives than ground ball pitchers.
Wyers’ reason for excluding the outliers makes sense but is very speculative, so it’s hard to put a lot of faith in the 0.38 r^2. I think there’s probably a lot more at work here, but not much of it has to do with the parks themselves (just the air density, the batter’s eye, and the weather make sense as factors, to me).
I wonder what else influences the stringers, though — are they more likely to score a particular batted ball a line drive if it falls for a hit… or at least if an infielder attempts to catch it? Do they confuse hard hit liners that land further into the outfield with fly balls?
Strasburg was one of the unluckiest pitchers in baseball last year. Uh oh.
Well, my formula didn’t think so. It pegged him at 0.308. He has a career 0.306, and it was 0.311 last year. There’s not a lot of innings pitched to judge by, though (251.1 career).
For the second formula, could you plug in career rates for the batted-ball data and have a sort of absolute range of a player’s xBABIP? Assuming there’s no change in park or pitching philosophy.
Yeah, my formula was really derived from looking at career rates, anyway (well, since 2002, anyway, because that’s as far back as the batted ball info goes on FanGraphs). The article I’m waiting on to be published talks about the ranges of how accurate it is, depending on how many innings pitched you have to go by.
Since popup rate, but especially LD%, are not very consistent from year to year, you’re better off using the average of years worth of data. Perhaps the more recent years should be weighted more heavily, though — I haven’t tested that, really.
Excellent stuff Steve, (and a wonderful article, Eno).
I’m real excited to see what the analysis has to show. I’m just finally getting around to dipping my toes into the analytical side of the game, and I gotta say, the water’s fine.