An in Depth Look at the 2015 Strike Zone

The Setup

It seems every day in every game there are at least a handful of calls by the home-plate umpire which defy reasoning. In Tuesdays game against St. Louis Ender Inciarte checked a bunt attempt for a ball that was in the dirt.  He was given a strike because the umpire thought it hit his bat.  All views of the replay show that Ender didn't just miss the ball with his bat, he didn't come within 2 feet of it.  Even after conferring with another umpire the call stood.  Unfortunately there were no grounds for review under the current system.  Ender was vindicated later when he hit a single back up the middle, but such poor calls do not always go requited.

Probably the worst strike zone ever recorded happened during the 1997 NLCS in game 5.  Umpire Eric Gregg could be considered to have single-handedly been responsible for the Livan Hernandez complete game.  Here is some video: https://www.youtube.com/watch?v=mR3eK5gCChM

It wasn't just bad, it was consistently other batters box bad.

The Pitch

I thought it would be good to go on an excursion to see if there was any data on umpire effectiveness behind the plate.  Most of us breath a large sigh when we hear Angel Hernandez, or CB Bucknor will be straddling the catchers box.  But how warranted are those reactions?  Do Angel and CB truly have 2 of the worst strike zones?  What is the average failure rate for the umpire to recognize genuine balls from strikes?

Using data from BaseballSavant.com I did some minor querying and calculating to see what interesting factoids I could dig up on this years class of umpires.  These numbers do not include pitches swung on for strike.

2015

Umpire	Pitches (In Zone)	Percent Called Ball	Pitches (Out Of Zone)	Percent Called Strike	Bad Call Percent
Bruce Dreckman	293	11.6	846	17.61	16.07
Tony Randazzo	250	11.2	805	17.27	15.83
Tim Welke	276	13.41	907	16.32	15.64
Victor Carapazza	219	11.87	708	16.67	15.53
Mike DiMuro	303	12.87	1044	15.9	15.22
Ed Hickox	181	12.15	589	15.96	15.06
Bob Davidson	301	9.63	992	16.43	14.85
Ted Barrett	426	12.91	1375	15.42	14.83
Dan Iassogna	333	8.71	1097	16.59	14.76
Sam Holbrook	323	13.93	865	15.03	14.73
Andy Fletcher	335	10.15	1215	15.88	14.65
Chris Segal	207	7.73	674	16.62	14.53
Lance Barrett	339	7.67	986	16.84	14.49
Dana DeMuth	310	13.23	981	14.88	14.48
Brian Knight	280	11.43	822	15.45	14.43
Bill Miller	318	7.23	911	16.9	14.4
Hunter Wendelstedt	240	9.17	804	15.92	14.37
Gary Cederstrom	262	9.16	789	16.1	14.37
D.J. Reyburn	167	11.38	538	15.24	14.33
Ron Kulpa	329	8.81	982	16.09	14.26
Dan Bellino	305	9.51	944	15.68	14.17
John Hirschbeck	338	6.51	1163	16.34	14.12
Rob Drake	279	14.7	855	13.92	14.11
Jerry Layne	257	13.23	822	14.36	14.09
Al Porter	225	12.44	621	14.65	14.07
Tom Hallion	320	12.5	967	14.48	13.99
Kerwin Danley	195	15.38	594	13.47	13.94
David Rackley	281	11.39	905	14.7	13.91
Mark Ripperger	258	9.69	693	15.44	13.88
Larry Vanover	359	11.7	1033	14.62	13.86
Adrian Johnson	249	8.43	799	15.52	13.84
Sean Barber	293	12.63	880	14.2	13.81
Paul Nauert	185	9.73	670	14.93	13.8
Brian ONora	221	9.5	750	15.07	13.8
Mark Wegner	372	11.02	1202	14.64	13.79
Dale Scott	312	11.54	932	14.38	13.67
Mike Winters	400	10.25	1169	14.8	13.64
Angel Hernandez	342	5.56	1135	16.04	13.61
Chris Conroy	302	11.92	881	14.19	13.61
Joe West	387	13.7	1050	13.52	13.57
Laz Diaz	309	13.27	994	13.48	13.43
Jeff Nelson	292	6.85	1012	15.32	13.42
Brian Gorman	316	8.86	1015	14.78	13.37
Jim Wolf	299	9.03	887	14.77	13.32
Marty Foster	388	8.25	1325	14.79	13.31
Manny Gonzalez	342	8.48	1063	14.86	13.31
Jordan Baker	380	12.37	1120	13.57	13.27
Marvin Hudson	360	10	1049	14.3	13.2
Todd Tichenor	300	11	883	13.93	13.19
Adam Hamari	363	6.06	913	15.99	13.17
Mike Everitt	285	7.02	928	14.98	13.11
Cory Blaser	297	9.43	885	14.35	13.11
Paul Emmel	289	9.34	925	14.27	13.1
Doug Eddings	321	5.92	838	15.75	13.03
James Hoye	355	12.96	1045	13.01	13
Clint Fagan	296	5.07	873	15.69	13
Alfonso Marquez	332	11.75	985	13.4	12.98
Gerry Davis	323	12.69	921	13.03	12.94
Bill Welke	343	11.95	1056	13.07	12.79
Quinn Wolcott	142	6.34	492	14.63	12.78
Jerry Meals	424	12.26	1291	12.94	12.77
Mike Estabrook	269	10.41	767	13.56	12.74
Greg Gibson	311	13.83	1030	12.33	12.68
Jim Joyce	392	12.76	1102	12.61	12.65
Mike Muchlinski	311	8.68	937	13.87	12.58
Gabe Morales	323	7.12	1027	14.22	12.52
Pat Hoberg	92	9.78	324	13.27	12.5
Eric Cooper	290	4.14	910	15.05	12.42
Phil Cuzzi	312	6.09	964	14.42	12.38
Ryan Blakney	202	10.89	604	12.75	12.28
Chad Fairchild	367	8.72	1087	13.43	12.24
Scott Barry	348	8.33	1066	13.51	12.23
Ben May	28	3.57	95	14.74	12.2
CB Bucknor	374	10.7	1013	12.73	12.18
Mark Carlson	334	10.18	1086	12.8	12.18
Jeff Kellogg	301	11.63	926	12.31	12.14
Fieldin Culbreth	181	11.05	552	12.5	12.14
Toby Basner	279	6.45	916	13.86	12.13
Chris Guccione	284	11.27	878	12.19	11.96
John Tumpane	347	11.53	1039	11.93	11.83
Paul Schrieber	265	10.19	846	12.17	11.7
Tripp Gibson III	261	8.05	843	12.34	11.32
Will Little	245	6.53	768	12.76	11.25
Jim Reynolds	293	6.48	916	12.66	11.17
Tim Timmons	310	8.71	973	11.92	11.15
Lance Barksdale	292	5.48	878	12.76	10.94
Tom Woodring	44	4.55	132	8.33	7.39

It seems the worst offenders are getting about 15-16% of their ball and strike calls wrong, while the best with at least 500 pitches seen get 11% wrong.  That makes about 1 out of every 9 pitches called incorrectly at the highest level of competence.  That would also mean there is at least one call for every half inning being called incorrectly on average.

Also from the data we can see which umpires tend to have a bigger strike zone, and which have a smaller strike zone.  Though, this information doesn't tell us if it's a wider or taller strike zone, just that it is bigger.

Kerwin Danley appears to have the smallest strike zone of any umpire in the game with a percentage of 15.38 strikes being called ball.  On the flip side Bruce Dreckman appears to have the largest strike zone with a whopping 17.61 percent of balls being called strike.  Not far behind Bruce is Tony Randazzo who's missing 17.27 percent of ball calls.

But who are the best at calling a ball a ball, and who is the best at calling a strike a strike?  Eric Cooper has the best eye for calling a strike a strike with a clean 4.14%, and probably most surprising Angel Hernandez has only gotten 5.56% of strike calls wrong.

It's not all roses for Angel though as his strike zone is quite horrendous with 16.04% of pitches out of the zone being called a strike.

The Call

As a result of Angel's 10% differential I realized that the average percent of incorrect calls might be a good way to determine just how often an umpire gets a ball or strike call wrong, but we can now also determine their bias toward strike or ball calls.

Umpire	Differential
Ben May	11.17
Eric Cooper	10.91
Clint Fagan	10.62
Angel Hernandez	10.48
Adam Hamari	9.93
John Hirschbeck	9.83
Doug Eddings	9.83
Bill Miller	9.67
Lance Barrett	9.17
Chris Segal	8.89
Jeff Nelson	8.47
Phil Cuzzi	8.33
Quinn Wolcott	8.29
Mike Everitt	7.96
Dan Iassogna	7.88
Toby Basner	7.41
Lance Barksdale	7.28
Ron Kulpa	7.28
Gabe Morales	7.1
Adrian Johnson	7.09
Gary Cederstrom	6.94
Bob Davidson	6.8
Hunter Wendelstedt	6.75
Marty Foster	6.54
Manny Gonzalez	6.38
Will Little	6.23
Jim Reynolds	6.18
Dan Bellino	6.17
Tony Randazzo	6.07
Bruce Dreckman	6.01
Brian Gorman	5.92
Mark Ripperger	5.75
Jim Wolf	5.74
Andy Fletcher	5.73
Brian ONora	5.57
Paul Nauert	5.2
Mike Muchlinski	5.19
Scott Barry	5.18
Paul Emmel	4.93
Cory Blaser	4.92
Victor Carapazza	4.8
Chad Fairchild	4.71
Mike Winters	4.55
Marvin Hudson	4.3
Tripp Gibson III	4.29
Brian Knight	4.02
D.J. Reyburn	3.86
Ed Hickox	3.81
Tom Woodring	3.78
Mark Wegner	3.62
Pat Hoberg	3.49
David Rackley	3.31
Tim Timmons	3.21
Mike Estabrook	3.15
Mike DiMuro	3.03
Todd Tichenor	2.93
Larry Vanover	2.92
Tim Welke	2.91
Dale Scott	2.84
Mark Carlson	2.62
Ted Barrett	2.51
Chris Conroy	2.27
Al Porter	2.21
CB Bucknor	2.03
Paul Schrieber	1.98
Tom Hallion	1.98
Ryan Blakney	1.86
Dana DeMuth	1.65
Alfonso Marquez	1.65
Sean Barber	1.57
Fieldin Culbreth	1.45
Jordan Baker	1.2
Jerry Layne	1.13
Bill Welke	1.12
Sam Holbrook	1.1
Chris Guccione	0.92
Jerry Meals	0.68
Jeff Kellogg	0.68
John Tumpane	0.4
Gerry Davis	0.34
Laz Diaz	0.21
James Hoye	0.05
Jim Joyce	-0.15
Joe West	-0.18
Rob Drake	-0.78
Greg Gibson	-1.5
Kerwin Danley	-1.91

* Positive value shows bias toward calling strikes.  Negative values show bias toward calling balls.

Based on this list, it seems the most unbiased umpires out there are James Hoye, Jim Joyce, Joe West, and Laz Diaz.  They incorrectly call balls and strikes about an equal percentage of the time.  Eric Cooper, though having a stellar track record of calling a strike a strike, looks to only be that good at strike calling because he's willing to call so many balls strikes as well.

Lastly, there appears to be a strong bias among the majority of umpires to call more balls strikes and thus "pitcher friendly".  I thought it would be interesting to compare these statistics to an earlier year, lets say 2008.

2008

Umpire	Differential
Doug Eddings	4.3
Phil Cuzzi	2.39
Bill Miller	2.36
Mike Muchlinski	2.29
Laz Diaz	2.21
Jim Wolf	1.92
Jeff Nelson	1.16
Brian Runge	0.72
Dan Iassogna	0.62
Damien Beal	0.54
Eric Cooper	0.45
Bruce Dreckman	0.35
Jim Reynolds	0.15
Brian Gorman	0.13
Gary Cederstrom	0.02
Mike DiMuro	0
Rob Drake	-0.09
Mike Everitt	-0.2
Ron Kulpa	-0.67
Jim Joyce	-0.75
Chuck Meriwether	-0.76
CB Bucknor	-0.83
Paul Emmel	-0.9
Angel Hernandez	-1.14
Bob Davidson	-1.21
Dana DeMuth	-1.48
Bill Welke	-1.58
Marty Foster	-1.6
Delfin Colon	-1.67
Mike Reilly	-2.08
Tim Welke	-2.26
Fieldin Culbreth	-2.26
Charlie Reliford	-2.3
Lance Barksdale	-2.38
Brian ONora	-2.38
Paul Nauert	-2.4
Gary Darling	-2.43
Ted Barrett	-2.48
Andy Fletcher	-2.75
Ed Rapuano	-2.85
Greg Gibson	-2.91
Chad Fairchild	-2.95
Mike Estabrook	-3
Mark Carlson	-3.07
Hunter Wendelstedt	-3.13
Wally Bell	-3.22
Alfonso Marquez	-3.22
Angel Campos	-3.29
Tim McClelland	-3.32
Scott Barry	-3.34
Marvin Hudson	-3.44
Todd Tichenor	-3.48
Chris Tiller	-3.51
Jeff Kellogg	-3.52
Chris Guccione	-3.54
Sam Holbrook	-3.67
Mike Winters	-3.69
Tom Hallion	-3.87
Dale Scott	-3.93
Joe West	-3.97
Ed Montague	-3.97
Kerwin Danley	-4.15
Kevin Causey	-4.34
Derryl Cousins	-4.35
Bill Hohn	-4.55
Mark Wegner	-4.83
Jerry Meals	-4.83
Brian Knight	-4.9
Tim Timmons	-5.04
Adrian Johnson	-5.27
Ed Hickox	-5.43
Tim Tschida	-5.74
Gerry Davis	-5.8
D.J. Reyburn	-5.8
Jerry Layne	-5.82
Larry Vanover	-6.77
Randy Marsh	-7.51
Casey Moser	-7.8
James Hoye	-7.93
Paul Schrieber	-10.39
Rick Reed	-11.16
Jerry Crawford	-11.19
Shawn Rakos	-11.42

* Positive value shows bias toward calling strikes.  Negative values show bias toward calling balls.

Well that's quite a bit different now isn't it.  7 years ago the strike zone was much more hitter friendly with a 2.85% bias towards calling a ball, versus a 4.51% bias towards calling a strike today.  That's a full 7% shift in mentality to be more pitcher friendly.

These values seem to indicate pitching may have not gotten better as many commentators have stated, but rather the umpires have adjusted the strikezone on a national scale to favor the pitcher.

Just to round out the statistical data for your viewing, here is the 2008 data for incorrect ball and strike calls.

2008

Umpire	Pitches (In Zone)	Percent Called Ball	Pitches (Out Of Zone)	Percent Called Strike	Bad Call Percent
Shawn Rakos	1136	24.68	279	13.26	22.4
Delfin Colon	1302	22.22	219	20.55	21.96
Rick Reed	1231	25.46	1287	14.3	19.74
Mark Carlson	1400	19.35	129	16.28	19.1
Tim Welke	49	20.54	3874	18.28	18.3
Brian ONora	1238	20.05	3627	17.67	18.27
Kerwin Danley	1199	20.66	3035	16.51	17.69
Mike Winters	1297	20.4	3681	16.71	17.68
Hunter Wendelstedt	1256	19.98	4035	16.85	17.6
Doug Eddings	1305	14.36	3998	18.66	17.59
Todd Tichenor	1204	19.2	1336	15.72	17.36
Alfonso Marquez	229	20.36	4271	17.14	17.31
Wally Bell	970	19.85	4102	16.63	17.25
Brian Gorman	164	17.08	3625	17.21	17.21
Bill Hohn	1208	20.41	2969	15.86	17.19
Damien Beal	1291	16.98	742	17.52	17.17
Bruce Dreckman	1226	16.86	3894	17.21	17.13
Paul Emmel	1365	17.74	3700	16.84	17.08
Angel Campos	1274	19.36	2888	16.07	17.08
Paul Nauert	1374	18.8	3780	16.4	17.04
Rob Drake	926	17.02	4163	16.93	16.96
Charlie Reliford	1275	18.56	3044	16.26	16.95
Mark Wegner	1110	20.67	4079	15.84	16.86
Gary Cederstrom	1278	16.82	4067	16.84	16.84
Scott Barry	1308	19.19	3343	15.85	16.79
Brian Runge	826	16.17	3612	16.89	16.76
Randy Marsh	1007	21.93	2289	14.42	16.72
Ed Hickox	1273	20.76	3738	15.33	16.7
Jeff Nelson	818	15.72	3530	16.88	16.67
Tom Hallion	1373	19.51	3818	15.64	16.66
Jerry Meals	1304	20.27	4002	15.44	16.62
Andy Fletcher	1263	18.69	3839	15.94	16.62
Bob Davidson	1268	17.51	4073	16.3	16.59
Bill Miller	1193	14.76	4065	17.12	16.58
Jim Joyce	1191	17.16	3822	16.41	16.58
Tim Tschida	1216	20.91	3810	15.17	16.55
Ed Montague	1377	19.13	2704	15.16	16.49
Ron Kulpa	1260	16.99	3683	16.32	16.49
Ted Barrett	1253	18.34	3822	15.86	16.47
Tim Timmons	1144	20.39	4027	15.35	16.46
Bill Welke	72	17.86	4048	16.28	16.31
Jim Reynolds	1257	16.17	4161	16.32	16.28
Chuck Meriwether	1266	16.86	3819	16.1	16.28
Paul Schrieber	1316	23.88	3596	13.49	16.27
Adrian Johnson	1360	20.23	4110	14.96	16.27
Larry Vanover	1328	21.21	3678	14.44	16.24
Laz Diaz	1171	14.53	3900	16.74	16.23
Ed Rapuano	939	18.52	4053	15.67	16.21
Dale Scott	1513	19	3796	15.07	16.18
D.J. Reyburn	1253	17.68	463	11.88	16.14
Marvin Hudson	1276	18.7	3859	15.26	16.12
Marty Foster	77	17.68	3720	16.08	16.12
Jerry Crawford	1249	23.7	2645	12.51	16.1
Dan Iassogna	886	15.59	3647	16.21	16.08
Dana DeMuth	1158	17.22	3654	15.74	16.08
Mike Everitt	1339	15.93	3866	15.73	15.77
Mike Estabrook	1373	17.73	2552	14.73	15.77
Sam Holbrook	1254	18.57	4061	14.9	15.77
Brian Knight	1212	19.47	3856	14.57	15.75
Jerry Layne	249	21.12	3771	15.3	15.67
Casey Moser	1320	16.33	129	8.53	15.67
Kevin Causey	725	18.23	1073	13.89	15.63
Chris Guccione	1270	18.31	4144	14.77	15.61
Angel Hernandez	212	16.57	3811	15.43	15.49
Mike Reilly	427	17.33	3883	15.25	15.45
James Hoye	1187	21.74	4556	13.81	15.44
Greg Gibson	1316	17.65	4275	14.74	15.42
Derryl Cousins	1263	18.69	3885	14.34	15.4
Mike Muchlinski	1193	14.46	758	16.75	15.38
Mike DiMuro	1278	15.33	3652	15.33	15.33
Gary Darling	1280	17.1	3674	14.67	15.3
Phil Cuzzi	1252	13.51	3611	15.9	15.28
Joe West	1139	18.3	3825	14.33	15.23
Jim Wolf	1271	13.75	4001	15.67	15.21
Jeff Kellogg	1239	17.74	3825	14.22	15.09
Chris Tiller	1309	16.16	656	12.65	15.01
Fieldin Culbreth	1275	16.7	3886	14.44	15
CB Bucknor	1305	15.53	3618	14.7	14.93
Chad Fairchild	1296	16.97	4209	14.02	14.71
Lance Barksdale	436	16.47	3924	14.09	14.33
Eric Cooper	373	13.86	3739	14.31	14.28
Tim McClelland	1202	16.2	3829	12.88	13.68
Gerry Davis	31	18.35	3792	12.55	12.61

I'd have to say it's a good thing the league didn't keep Shawn Rakos and Delfin Colon around too long.

I'm Out

So what type of conclusions can we draw on this data?  Well I'd say there's been a dramatic shift at the MLB level to be more pitcher friendly.  I find it very hard to believe that collectively all umpires have just changed their tendencies without some sort of outside influence.  I guess I'll leave that up to the reader to decide what that influence was.

What might have gotten missed by everyone is how much better the calls have gotten.  In 2008 the average of incorrect calls was 16.42%, this year it's 13.32%.  That's a 3.1% improvement from 2008.  Whatever the league is doing it seems to be doing it right.