SABR's Statistical Analysis Committee

by: Tom Hanrahan

When someone postulates “this guy was the greatest pitcher of all time (the GOAT)”, there is a multitude of numbers and narratives that are used. Some of the more obvious simple ones are

Cy Young: won 511 games (most WAR also, per baseball-reference.com)

Walter Johnson: 411 wins for poor teams, and a 2.17 ERA

Lefty Grove: 9 ERA titles, highest winning pct among 300-game winners

Christy Mathewson: 373 wins, only 188 losses

Warren Spahn: 363 wins, even with 3 missed years for WWII

Roger Clemens, 7 Cy Young awards

Nolan Ryan:  5714 Kos & 7 no-hitters

Bob Gibson: ultimate clutch big-game pitcher, and 1968 ERA of 1.12

Satchel Paige: greatest Negro League pitcher, pitched for over 30 years

Mariano Rivera: best reliever, and first unanimous HoFer

Sandy Koufax: 5 consecutive ERA titles, 111 wins, 34 losses

The problem with all of these, is there is always a “but…”. Cy Young threw a dead rag ball every 3^rd day; the conditions were Very different. Nolan Ryan walked the most batters ever. Bob Gibson led the league in Wins and ERA only once each. Koufax retired very young. On and on. Perhaps the biggest BUT in these GOAT arguments is that when one pitcher is put forth as the GOAT, almost always there is a contemporary of said pitcher with similar numbers.. and if it is not obvious that A is better than contemporary B, how can we confidently choose A as the GOAT? Walter Johnson was indeed dominant… but he pitched parts of his career nearly alongside Pete Alexander (who was his equal for a long while), as well as Matty, and Grove, even a few years of Young’s career. While there is a consensus that the Big Train was numero uno over the course of his 21-year career, once you extend back to 1900, or forward to 1935, the picture gets murky. Ditto for the modern studs: Maddux and Pedro were amazing, but so was Randy Johnson, and then there is Rocket Man; who has the best modern numbers of all, but many dismiss his later accomplishments because of steroid use.

So, I propose this approach to the GOAT pitcher argument: find the pitcher who was clearly the BEST, for the LONGEST time. In other words, about whom can you say “it is pretty clear that he was the greatest pitcher between the years XX and YY”, where the time period between XX and YY is longer than any other man who toed the rubber.

What do I mean by this? Let’s start with some examples. Okay, Pedro Martinez, 1999-2000; over 2 those two seasons, his “adjusted ERA” (using baseball-reference) was merely 38% of the average; if the typical pitcher gave up 8 runs over 2 games, Pedro gave up only 3! Fine, he was definitely the best for 2 years… but 2 years is not that long; if you move forward to include 2001, maybe Randy Johnson was as good.

Can we do better than that? Sure; I nominate Sandy Koufax, 1962-66; it is Very obvious, is it not, that Sandy was the dominant guy for those 5 years? In fact, you can include 1967, even though Sandy was retired, add no one touches him. Move back to also include 1961, and I would say for that 7 year window, Sandy was clearly #1.

Moving on; Walter Johnson says, I can top that. In the 1910s, Johnson had the most of everything; Wins, Win Shares, WAR, ERA titles, you name it. And it doesn’t stop at 1910-1929; you can use the Big Train’s whole career, 21 years, and if I showed all of the numbers, it would be clear no one touches him. Begin going outside of his career, maybe back to 1900, forward to 1934… it is pretty easy to build a case that a clear consensus exists that Johnson was the best pitcher in the first third of the 20^th century. THAT is a long time. Could anyone top it?

Using this approach, I will show that the answer of who the best for the longest time is … Tom Seaver.  

I begin by finding the period (XX to YY) over which Seaver was the best pitcher, without anyone else having too strong of an argument otherwise. 

Okay, so how does one confidently measure “best”; what metrics to use? I offer that a pitcher must have a combination of career accomplishments, plus must-have performed at a high level over their peak or prime. You can’t be the best if you flamed out after a brief period, nor if you merely accumulated wins without ever being an ace… you need both.

For career or bulk weight, I will use two common metrics; Bill James’ Win Shares, and baseball-reference WAR; as well as the basic career stats of Wins, Losses, and ERA. For excellence, I will use baseball-reference Wins Above Average (WAA), and I will also calculate Wins Above Team (WAT), explained below; both of these measure how many Wins (WAA measurers runs and formulas them into Wins) above an average pitcher (in MLB, or on his team) he was worth.

WAT – Instead of using earned Runs allowed as the primary measure, WAT uses a pitchers’ actual W-L record, and compares it to his team’s W-L record in all games where this pitcher did not get a decision. Example:

In 1972, Steve Carlton famously went 27-10 for a Phillies team which finished the season 59-97. So the Phillies’ record other-than-Carlton was 32-87, for a winning pct of .269. Seaver’s wpct was .730, an improvement over the team of .461. Over Carlton’s 37 decisions, he won 17.1 more games than the pace his teammates set. Lefty’s 17.1 WAT in ’72 is an astounding figure that may not ever be reached again in one year.

So, we have basic W–L and ERA; WS and WAR; and WAA and WAT. We will start with Seaver’s career, which ran from 1967 to 1986. I found the pitchers who had the most WS in those years. They are listed in table 1, (sorted by career WS) along with the other statistics mentioned above. In some cases, the pitchers also pitched outside of this 20-year period; I will address that a bit further on.

Table 1 :Stats for top pitchers, 1967-1986

Pitcher	W	L	ERA	WS	WAR	WAA	WAT
T Seaver	311	205	2.86	388	106	65	58
P Niekro	305	255	3.27	363	97	53	41
S Carlton	320	226	3.12	358	84	37	39
G Perry	269	227	3.05	321	83	43	27
F Jenkins	276	217	3.34	309	78	40	28
J Palmer	248	138	2.80	297	66	33	19

By almost every measure, Tom Seaver as the best pitcher over this 20-year span. The only measures he does NOT lead in among these arms is that Jim Palmer had a lower raw ERA, and a higher raw winning percentage. And, it is fairly obvious from the data and from those who watched the Orioles in this time period, that Mr. Palmer benefited greatly from possibly the best defense ever assembled, and from teammates who scored plenty of runs in support of him.

Having established a solid 20-year period of greatness, how do we find the length over which the “best in the business” record extends? I will go backwards in time before 1967, and then forwards after 1986, to see where another pitcher comes close enough to Seaver’s marks to change the verdict for clearly best to “unclear”.

Moving backwards thru the early 60s to late 50s, we see Bob Gibson and Sandy Koufax as bright lights, but Koufax’s comet was short-lived, and Gibson for all of his reputation can really only show one incredible season (1968!) and excellent World Series pitching as marks in his favor; and Seaver’s post-season records are not shabby (8 starts against the Aaron Braves, the Robinson Orioles,  the Reggie A’s, the Big Red Machine, and the Stargell Pirates; for an ERA of 2.77). Once we go back to 1950, Robin Roberts has much merit, but his W-L record of 286-245 falls short. It is not until we get most of Warren Spahn’s career that another worthy candidate emerges. Spahn has 412 Win Shares, more than Tom Terrific, so we need to examine the two of them. By taking in Spahn’s whole career (minus a few innings prior to WWII), it is no longer obvious that Seaver is the better pitcher:

Table 2: Stats for Seaver and Spahn, covering 1946-1986

Pitcher	W	L	ERA	WS	WAR	WAA	WAT
T Seaver	311	205	2.86	388	106	65	58
W Spahn	363	245	3.08	412	93	42	44

So, how far into Spahn’s career do we have to “eat” before it is clear that Seaver is better? If we take away Spahn’s first good season in 1947 with 21 wins and an ERA title, it seems obvious. Thus, I will re-run the table, now including Spahn and Gibson while dropping Jenkins and Perry, going forward from 1948:

Table 3: Stats for top pitchers, 1948-1986

Pitcher	W	L	ERA	WS	WAR	WAA	WAT
T Seaver	311	205	2.86	388	106	65	58
P Niekro	305	255	3.27	363	97	53	41
S Carlton	320	226	3.12	358	84	37	39
W Spahn	334	230	3.13	371	81	34	38
B Gibson	251	174	2.91	309	82	47	32
J Palmer	248	138	2.80	297	66	33	19

Spahn leads in Wins, which is a reflection of his great career length, plus the good Braves teams for which he pitched. Again, by virtually every measure, Seaver is #1 for this period, which is now up to 39 seasons.

Now, let’s move forward. As the 80s turned to the 90s, a new generation of super pitchers emerged, highlighted by Greg Maddux and Roger Clemens. Certainly as their careers wound down, many could see them both as equal to or better than Seaver. But where in their careers was it still obvious that neither of them HAD “caught” Seaver? By 1996, Maddux had 4 consecutive Cy Young awards, 4 ERA titles, 165 career wins; and Clemens had 3 CY’s, 4 ERA titles, 192 wins, and a WAA over 55, approaching Seaver’s career totals. That makes for an ambiguous judgment call.  But if we go back to 1994, we delete 20 of Clemens’ wins, and one of Maddux’s amazing years (19-2, 1.63 ERA). Let’s view their totals thru 1994, compared with Seaver:

Table 4: Stats for selected pitchers, 1948-1994

Pitcher	W	L	ERA	WS	WAR	WAA	WAT
T Seaver	311	205	2.86	388	106	65	58
R Clemens	172	93	2.93	220	71	50	43
G Maddux	131	91	3.02	152	41	25	25

Rocket Man has a better winning percentage, but trails by large amounts in every other category. Yes, by 1994, these and other pitchers were on their way to great careers, but much of that was still to come.

At this point, it would seem that Seaver has a claim to the 47 years 1948-1994 as one where he could be called clearly the best pitcher of that lengthy period. One more table, including the pitchers considered so far, along with others who are often thought of as great post-integration hurlers. Here I’ve added a column, Wins minus Losses, on the right. The leader in each category is in red, with 2^nd place in blue.

Table 5: Stats for top pitchers, 1948-1994

Pitcher	W	L	ERA	WS	WAR	WAA	WAT	W – L
T Seaver	311	205	2.86	388	106	65	58	106
P Niekro	305	255	3.27	363	97	53	41	50
N Ryan	324	292	3.19	334	84	35	22	32
R Clemens	172	93	2.93	220	71	50	43	79
S Koufax	165	87	2.76	194	53	31	28	78
S Carlton	320	226	3.12	358	84	37	39	94
W Spahn	334	230	3.13	371	81	34	38	104
B Gibson	251	174	2.91	309	82	47	32	77
J Palmer	248	138	2.80	297	66	33	19	110

Tom Seaver has the most WAR, WAA, and WAT; and by good margins in most cases. He is second only to Palmer in raw W – L, and obviously this is due to the quality of the Oriole teammates compared to Seaver’s Met teammates. I believe this table summarizes why I believe, and I would hope most would agree, that Seaver had no equal over this 47 year period. Again, this is not saying that some pitchers in this period were better than Seaver for brief periods; it is that when the entire period is used, Seaver is clearly #1.

Having established this, the next step would be to find other pitchers for whom you could make a good case of their being the best pitcher for similar long periods of time. This, it turns out, is the easier piece of the analysis; it quickly becomes clear that NO ONE had anywhere near such a length of dominance.

In the modern era, Roger Clemens has been the most dominant and successful pitcher by most any measure… but. Many would point to his seeming reliance on illegal performance enhancing supplements as a valid reason to discount his accomplishments, just as those of Barry Bonds have been., Any pitcher who is not in the Hall of Fame surely cannot be clearly assessed as the best pitcher of any time frame.

Going back in time before Seaver, we have great hurlers like Lefty Grove (300-141, 9 ERA titles), Walter Johnson (411 wins for most-poor Senators teams) and of course Cy Young (511 wins!). Grove dominated the mid 20s through 30s; Johnson the teens; Young the 90s and early 00s. Each was awesome in his time… but once you begin extending the time period, they compete with each other. Johnson COULD be the greatest pitcher of all time, but it cannot be said it is obvious that was the best over any 45 year period, which would need to include either Young’s career, or Grove’s. Lefty Grove had no equal in the years after he retired, so I could make a good claim as MLB’s best pitcher for 45 years, from 1915 to 1959. This, however, does not include the overlapping career of the man who is acclaimed as the greatest Negro League pitcher ever, and possibly the greatest pitcher of any league… one Leroy “Satchel” Paige, whose career runs from about 1925 to 1953.  Is it obvious that Grove is Satchel’s superior? I don’t see how it can be obvious. Paige would also be a part-contemporary of Warren Spahn, throwing doubt on an argument for the great Brave hurler.

Cy Young is the most accomplished pitcher in terms of career achievements from the dawn of the NL to at least through the late 1910s… but it is difficult to assess if others like Kid Nichols or Old Hoss Radbourne or Tim Keefe may have been better in the murky and rapidly-changing 1880s and 1890s. And the NL did not begin until 1876. In order to get Young to 47 years, you would have to go back to the National Association of the early 1870s, and who is to say that Albert Spalding, who won 252 games and lost 65 in the NA’s 6 years, leading the league in virtually everything, wasn’t Cy’s superior? No, claiming 47 years for even Mr. Young is a bridge too far.

So what are we left with? Many can claim brief periods of dominance, such as Koufax for 6 to 10 years. Some can claim longer periods, like Cy Young for 20 to 40 years, or Lefty Grove if you don’t include the Negro Leagues. But nobody can touch the length of Tom Seaver’s era of almost unquestioned superiority. Does that make Tom Seaver the greatest pitcher ever? No. Just as it does not diminish Hank Aaron and Willie Mays’ greatness that they both were NL outfielders with concurrent careers, it must be admitted that the lack of a comparable pitcher could be just a happenstance, as is the confluence of the careers of Walter Johnson with others. If I were to choose a pitching staff for my all-time team, Seaver would not be #1. But he WOULD make my rotation. Because no one else can be said to have been the best pitcher for a period of almost 50 years.

by Alfredo Nasiff Fors

The barrage of Home runs this MLB season resulted in a stratospheric number of broken records. Each year has its own peculiarities, though not as remarkable as this 2019 when even the MLB Commissioner’s Office was prompted to admit that some changes were made to the ball. If we look at the HR/AB mean per season, we would see the differences from one year to another that, independently of the many causes, must be taken into consideration by statisticians when drawing comparisons among sluggers from different decades.

Source: Lahman database in R (for all graphs)

The trend indicates that nowadays, it is easier to hit Home runs than at the beginning of MLB history. We can speculate that if Babe Ruth would have played in modern times, the total of his Home runs would have been higher, but we certainly will never know that. Nevertheless, comparisons can be made among players from different times, weighing in their performances against the rest of the players of each Season played, meaning dividing the individual performance against the Season mean of the parameter we are studying.

The purpose of this paper is to make the comparison of the greatest Home run sluggers of all times against the mean of each season played by them.

We begin by presenting the case of Babe Ruth as an example. The following graph shows HR/AB by year with three lines drawn, one represents Babe Ruth’s index, another one represents the mean of the Season and the last one the Rate, which is [Babe Ruth (HR/AB)]/ [Season (HR/AB)]. In 1920 Babe Ruth HR/AB index was 0.118; the Season mean was 0.007; therefore, he had a frequency of HR/AB 15.8 times above average (the Rate).

Adding up the Rate index accumulated by Babe Ruth along his entire career will make a total of 157.2 times above Seasons mean:

How does this compare with the other players listed among the top HR sluggers, the following table shows it in descending order by number of HR:

	Name	Years	AB	HR	(HR/AB) / Season(HR/AB)
1	Barry Bonds	1986-2007	9847	762	61.2
2	Hank Aaron	1954-1976	12364	755	59.3
3	Babe Ruth	1914-1935	8398	714	157.2
4	Alex Rodriguez	1994-2016	10566	696	43
5	Willie Mays	1951-1973	10881	660	51.7
6	Albert Pujols	2001-2018	10196	633	36.6
7	Ken Griffey	1989-2010	9801	630	46.7
8	Jim Thome	1991-2012	8422	612	51.5
9	Sammy Sosa	1989-2007	8813	609	39.4
10	Frank Robinson	1956-1976	10006	586	53.9
11	Mark McGwire	1986-2001	6187	583	57.4
12	Harmon Killebrew	1954-1975	8147	573	54.5
13	Rafael Palmeiro	1986-2005	10472	569	36.8
14	Reggie Jackson	1967-1987	9864	563	51.3
15	Manny Ramirez	1993-2011	8244	555	41.2
16	Mike Schmidt	1972-1989	8352	548	50.2
17	David Ortiz	1997-2016	8640	541	37.4
18	Mickey Mantle	1951-1968	8102	536	47.8
19	Jimmie Foxx	1925-1945	8134	534	71.5
21	Frank Thomas	1990-2008	8199	521	43.1
22	Ted Williams	1939-1960	7706	521	67.4
20	Willie McCovey	1959-1980	8197	521	56.9
24	Eddie Mathews	1952-1968	8537	512	43.4
23	Ernie Banks	1953-1971	9421	512	40.7
25	Mel Ott	1926-1947	9456	511	70.4
26	Gary Sheffield	1988-2009	9217	509	42.8
27	Eddie Murray	1977-1997	11336	504	39.4
29	Fred McGriff	1986-2004	8757	493	41
28	Lou Gehrig	1923-1939	8001	493	63.7
30	Adrian Beltre	1998-2018	11068	477	29.1
31	Stan Musial	1941-1963	10972	475	43.2
32	Willie Stargell	1962-1982	7927	475	50.5
33	Carlos Delgado	1993-2009	7283	473	31.9
34	Chipper Jones	1993-2012	8984	468	30
36	Dave Winfield	1973-1995	11003	465	39.5
35	Miguel Cabrera	2003-2018	8456	465	28
38	Adam Dunn	2001-2014	6883	462	34.7
37	Jose Canseco	1985-2001	7057	462	44.5
39	Carl Yastrzemski	1961-1983	11988	452	38
40	Jeff Bagwell	1991-2005	7797	449	28.1
41	Vladimir Guerrero	1996-2011	8155	449	27.4
42	Dave Kingman	1971-1986	6677	442	58.6

up to 2018

At first glance, one thought jumps out from the table: Babe Ruth “(HR/AB) / Season (HR/AB)” more than double the next player in the list.

If we look carefully, will see that in recent years it is tougher for players to excel above the mean, note that the only two active players on the list are doing very badly in the Index, which can be explained by the rise in the mean as seen in the first chart, or in simple words, it is harder to be the leader when everybody else hit a lot of Homeruns. This trend has multifactorial causes, among them it will be explored the hypothesis that these days players hit more Home runs thanks to the rise in competitiveness due to the fact that the selection process is made from a larger number of players, Teams, Leagues, training camps, and international contracts, and the advancements made in the technology applied to enhance performance, which plays a major role in nutrition, fitness, statistics, etc.

Could factors such as competitiveness and enhanced performance be measured? The proposition is to use the weight and height of the players as an expression of how those factors have improved their physical traits and therefore quantify how has this affected the mean of HR per Season.

The “Strength” of players will be then, the addition of both their height (in inches) and weight (in lbs.), reasoning that the taller and corpulent the player the farther will go his connections. Plotting the mean of each season, the graph looks like this:

It is effectively seen that in recent times, the players are stronger, therefore making it harder for power hitters to excel above the mean. In 1920 the Strength mean was 243.2 while Babe’s Strength was 289, taking over 45 points of advantage. In 2011, the year Mike Trout debuted with a Strength of 309, the mean topped the all-time list with 285, a meager 24 points below.

Recalculating the “Times_HRperAB_over_SeasonMean” Rate dividing it by the “Times_Strength_over_SeasonMean” resulting in “Times HRRate_vs_StrengthRate”, shows the difference in “Diff_HRperAB_vs_Strength”:

	Name	Years	AB	HR	Strength	Times_HRperAB_ over_SeasonMean	Times_Strength_over _SeasonMean	Times_HRRate_ vs_StrengthRate	Diff_HRperAB _vs_Strength
1	Barry Bonds	1986-2007	9847	762	258	61.2	21.4	63.3	2.1
2	Hank Aaron	1954-1976	12364	755	252	59.3	22.5	60.7	1.4
3	Babe Ruth	1914-1935	8398	714	289	157.2	25.9	133.2	-24
4	Alex Rodriguez	1994-2016	10566	696	305	43	24.4	38.8	-4.2
5	Willie Mays	1951-1973	10881	660	240	51.7	21.4	55.5	3.8
6	Albert Pujols	2001-2018	10196	633	315	36.6	20.3	32.5	-4.1
7	Ken Griffey	1989-2010	9801	630	270	46.7	23	46.4	-0.3
8	Jim Thome	1991-2012	8422	612	326	51.5	29.9	43.2	-8.3
9	Sammy Sosa	1989-2007	8813	609	237	39.4	16.9	44.4	5
10	Frank Robinson	1956-1976	10006	586	256	53.9	21.9	54.2	0.3
11	Mark McGwire	1986-2001	6187	583	292	57.4	18.9	51.7	-5.7
12	Harmon Killebrew	1954-1975	8147	573	267	54.5	22.8	52.6	-1.9
13	Rafael Palmeiro	1986-2005	10472	569	252	36.8	19.1	38.7	1.9
14	Reggie Jackson	1967-1987	9864	563	267	51.3	21.8	49.5	-1.8
15	Manny Ramirez	1993-2011	8244	555	297	41.2	22.9	37.7	-3.5
16	Mike Schmidt	1972-1989	8352	548	269	50.2	18.8	48.1	-2.1
17	David Ortiz	1997-2016	8640	541	305	37.4	22	34.2	-3.2
18	Mickey Mantle	1951-1968	8102	536	266	47.8	18.6	46.3	-1.5
19	Jimmie Foxx	1925-1945	8134	534	267	71.5	22.4	67.1	-4.4
20	Willie McCovey	1959-1980	8197	521	274	56.9	24.4	53.6	-3.3
21	Frank Thomas	1990-2008	8199	521	317	43.1	23.6	36.5	-6.6
22	Ted Williams	1939-1960	7706	521	280	67.4	20.8	61.6	-5.8
23	Ernie Banks	1953-1971	9421	512	253	40.7	18.6	41.4	0.7
24	Eddie Mathews	1952-1968	8537	512	263	43.4	18.4	42.5	-0.9
25	Mel Ott	1926-1947	9456	511	239	70.4	21	73.9	3.5
26	Gary Sheffield	1988-2009	9217	509	261	42.8	23.4	43.8	1
27	Eddie Murray	1977-1997	11336	504	264	39.4	23.4	38.6	-0.8
28	Lou Gehrig	1923-1939	8001	493	272	63.7	18.6	58.1	-5.6
29	Fred McGriff	1986-2004	8757	493	275	41	21.9	39.2	-1.8
30	Adrian Beltre	1998-2018	11068	477	291	29.1	22	27.9	-1.2
31	Stan Musial	1941-1963	10972	475	247	43.2	21.2	44.8	1.6
32	Willie Stargell	1962-1982	7927	475	262	50.5	21.4	49.7	-0.8
33	Carlos Delgado	1993-2009	7283	473	290	31.9	18.2	29.8	-2.1
34	Chipper Jones	1993-2012	8984	468	286	30	19.9	28.6	-1.4
35	Miguel Cabrera	2003-2018	8456	465	325	28	18.5	24.3	-3.7
36	Dave Winfield	1973-1995	11003	465	298	39.5	26.5	34.3	-5.2
37	Jose Canseco	1985-2001	7057	462	316	44.5	22.9	36.9	-7.6
38	Adam Dunn	2001-2014	6883	462	363	34.7	20.8	26.8	-7.9
39	Carl Yastrzemski	1961-1983	11988	452	246	38	22	39.8	1.8
40	Jeff Bagwell	1991-2005	7797	449	267	28.1	15	28	-0.1
41	Vladimir Guerrero	1996-2011	8155	449	310	27.4	18.1	24.1	-3.3
42	Dave Kingman	1971-1986	6677	442	288	58.6	21.3	52.4	-6.2

The largest differences were accounted by Babe Ruth (-24) who still almost double his closest tracker (Mel Ott, who displaced Jimmie Foxx of the second place thanks to his low 239 Strength) and Sammy Sosa (+5). So, the physical traits of Babe Ruth (74 in + 215 lbs = 289) impacted negatively in his “Times HR/AB over Season mean”, as the other players of his time were in physical disadvantage with him, looking like kids playing around with a Pro.

Corollary

Babe Ruth, despite this later skirmish using the Strength statistic, seems to be once again, immovable as the Greatest Player of All-Time.

Big names show up topping the list of the “Times HRRate_vs_StrengthRate”: 1-Babe Ruth; 2-Mel Ott; 3-Jimmie Foxx; 4-Barry Bonds; 5-Ted Williams; 6-Hank Aaron; 7-Lou Gehrig; 8-Willie Mays; 9-Frank Robinson; 10-Willie McCovey; 11-Harmon Killebrew. Make your own judgment.

 

Throughout the MLB’s long and storied history, narratives have defined fans’ enjoyment of the game as well as many teams’ front office strategies and teambuilding. From the fan perspective, these stories build the mythology and lore of the sport. But from the team perspective, these unbacked assumptions can often be harmful and limiting. One of the best examples of this is the long-held belief that only a special, “mentally tough” reliever is capable of handing the stress of finishing a game. These “proven closers” supposedly have the guts and experience to hold up under the immense weight of securing a save. This assumption has finally started to be questioned  in recent years as advanced analytical front offices have conducted rigorous testing on many of these ancient baseball narratives. This can be easily seen by doing a simple glance at who successful current teams trust with the role compared to ten years in the past.

For this study, I used players who had at least 75 saves in the years preceding the chosen year as my proven cutoff. These pitchers would have recorded enough experience to allegedly calm their nerves and earn the title of proven closer in the public baseball lexicon. During the 2010 season, 60 percent of the league’s top 15 teams had these guys finishing games. That’s lower than the previous decades, but is huge compared to this season: In 2019 only 40 percent of the top 15 teams fielded these wily, validated veterans. While some are top pitchers in the league, including the likes Aroldis Chapman, Craig Kimbrell, and Sean Doolittle, the other group is just as effective. Inexperienced guys like Luke Jackson, Josh Hader, and Taylor Rodgers have taken the league by storm, and while they often are not as publicly recognized, they are often just as effective.

This, however, is all just anecdotal evidence. For the rest of this paper, I will evaluate whether this recent strategical change is valid and if being a proven closer really does make you more qualified to man the most continuously stressful position in the game.

The first test I will be running is a general comparison between the “proven closer” and the not-proven (which I’ll call the “young’uns”) for 2010 and 2019. One interesting part of this comparison is that these relievers over their careers have each played both roles at certain points. Due to this, you obviously can’t just take career stats for guys with 75 saves and those without. This can be easily solved by taking each season as its own individual data point. This will cause players like Mariano Rivera to have around 15 data points in the proven closer bucket, meaning he will have a larger impact on the end results than, for example, Luke Jackson. But this is fair, as his sample is much larger and deserves to have higher weight than a guy who has pitched only 30 innings in save situations.

After I built the aforementioned datasets, I took weighted averages of the two groups’ performance in save situations. The statistics taken into account were ERA, WHIP, K/9, and OPS allowed. I would have preferred to use some different metrics, but the ease of Baseball Reference’s save situations splits led me to use their numbers, which should be more than fine for this exercise. I then took the means of each of the previous statistics for both player buckets. This was used to run Welch’s T tests, a statistical method which tests differences in datasets that have different sample sizes. The results for every stat were pretty comparable across the board and actually gave some good insights. I did expect the proven closers’ numbers to look relatively similar to the “young’uns” numbers, but with maybe slightly better results due to the higher weight on a few very good players, like Rivera and Hoffman. But what I found was the young’un group significantly outperformed their proven counterparts on all stats across the board. ERA, which is probably the most important stat I tested, had the young’un group coming in at a 2.95 ERA in save situations compared to a 3.09 ERA for the vets. This may not seem like a lot, but when this data is tested, that result ended with a .21 p value when the null hypothesis used was the proven group having a lower ERA. In more layman’s terms, this means that in this dataset, it is very unlikely that this difference was just random variation and that having 75 career saves does not lead to a lower ERA in save situations. This discovery was consistent among the other statistics. While this provides some evidence to prove the irrelevance of the proven closer motif, these results could have resulted from other biases in the dataset, including that the young’uns are, well, younger, and that most guys who recently entered the closer spot are playing at the top of their game. This makes it necessary to conduct further testing if we want to say more confidently that the “proven closer” is myth.

One of the main issues with doing overarching quantitative analysis on this subject is the biases created by the uneven opportunities given by teams. In other words, playing time is not randomly generated for the players in the league. Teams are trying to win, and it obviously hurts this goal to have subpar pitchers on the hill during the highest leverage part of the game. To account for this, we need to create a baseline talent for each player. That way we would isolate pitching in the 9^th inning as the only variable. To do this, I compiled the statistics for each player in the previous datasets for both save and not save situations. If having 9^th inning experience makes an actual difference, the proven closers bucket would show a much larger negative delta when compared to the young’uns.

 

The results were as follows:

	ERA Save SIt	ERA Non-Save Sit	OPS Save SIt	OPS Non-Save Sit
Proven Closer	3.11	3.39	.636	.663
Young’uns	3.65	3.75	.683	.705

 

As you can see the differences, while pretty similar, are larger for the proven closer group. This slightly points towards proven closers having an edge. But this is not as significant a difference as the previous study when taking into account the smaller sample size from not repeated players. This makes an interesting counterargument to the previous point and definitely requires further testing.

The last statistical method I used incorporated predictive modeling into the equation. This could potentially add an extra layer of noise to the study, but I believe it’s worth it if you take that into account.  My idea was to create a usable model that predicts a closer’s save situation ERA from a variety of different inputs, but excluding everything that has to do with experience in the role. A few examples are innings pitched, saves, and any counting stat. From this starting point, I was able to build an OK but admittedly limited multiple linear regression model with various rate based inputs ranging from FIP, to K%, to HR/9. My final model ended with a mean absolute error of .4 on the validation datasets, which means it on average missed its target by a distance of .4 ERA.

After this, I input my two proven and unproven data buckets and evaluated the error metrics for each. What I was looking for was the model to predict the proven players bucket significantly worse than they actually were, and the unproven players significantly better. This would show that there was some hidden skill not accounted for in the model on top of just random noise. While we can’t say for sure what that skill would be, I attempted to design a model that would make that the most likely missing piece.

The results were the exact opposite. The model predicted the unproven guys to be worse than they actually were while the proven guys to be better. This easily could have been just variation, so I decided to run another Welch’s T Test to evaluate how significant the difference in error was. It was very confident that the mean error did not predict better results than actually seen for the proven guys and worse results than actually seen for the unproven guys. This was evident by a .9997 p value, which is a very significant number. Of course, this has to be taken with a grain of salt due to the previously mentioned issue of the added noise from my not-perfect predictive model. Nevertheless, this level of certainty is good evidence and backs the idea that experience in the 9^th isn’t an important factor.

In conclusion, my quantitative studies, for the most part, back the industrywide trend of no longer relying on the archetypal “proven closer”. The abundance of 9th inning experience does not seem to make any significant, quantifiable difference. While the second test conducted didn’t back this claim, the other two studies more than did. This makes sense. A good pitcher is a good pitcher. And while it is difficult to deal with stress when you haven’t before, these are professional athletes who play on the biggest stage in the world. They deal with immense stress every day. In order to get to this level of excellence in this failure-based game, they have to be mentally tough. No matter how many career saves you have, pitching the 9^th inning of a close game with playoff applications is just another day at the office.

In baseball today, the importance of player development is no longer debatable. Everyone has rallied around the necessity of impactful training. Instead, battles are now erupting over which skills are crucial to develop in young players.

Pitchers are the focal point of these debates as new-school biometric training facilities have revolutionized the process by concentrating on improving spin, mechanics, and velocity. This strategy has been met with harsh counter claims from older-school coaches who emphasize repeatable mechanics, control, and pitch sequencing over the “glamour” skills that the newer biometric companies covet.

This battle has been waged in MLB front offices for years, and at this point, the new training seems to be winning. This past off-season, biometric data-driven coaches were brought in by numerous franchises. These guys are touted as the future of player development. But are the new skills that they focus on any more strongly positively correlated with MLB success than the older school skills? In this analysis, we will dive into the data and find out which underlining skills are the most crucial to big league success and whether these new school guys are in fact correct.

As you can probably guess, each individual skill will have a very low correlation to overall success. That’s because pitching is a complex conglomerate of skills that can be combined in myriad ways and still be very successful. There is no perfect mix. With that being said, when you compare each skill, you can still see which ones as a whole contribute most to the overall package and are, in general, the most crucial. The skills I chose to test are as follows, generically grouped into old school and new school:

Old School

Ability to locate pitches: Measured by BP’s CMD Metric

Ability to change speeds: Measured by velocity drop off between primary fastball and off-speed

A mixed arsenal: Measured by breaking ball, off-speed, and fastball percentages of pitches thrown.

New School

Fastball Velocity: Measured by highest average fastball velocity

Fastball Spin Rate: Measured by average RPM for 4 primary fastball

Slider Spin Rate: Measured by average Rpm for all pitchers who threw the offering at least 5% of the time

Curveball Spin Rate: Measured by average Rpm for all pitchers who threw the offering at least 5% of the time

The first step was isolating each variable’s effect on success. I quantified success as MLB ERA instead of more pitcher isolation based metrics like Fip. I did this for two reasons. The first is that Fip and its follower stats tend to be biased toward pitchers who lean towards the more new-school approach. This is due to the old -school approach’s emphasis on generating weak contact, which FIP factors out completely. Using ERA puts both skillsets on relatively the same playing field, even though it may give pitchers too much credit for weak contact in turn, slightly helping out the old school. Second, I wanted to measure the most basic definition of pitcher success: limiting runs. This keeps it simple and is easily understood by the general public.

After running simple linear regressions for each of my 9 variables (I split arsenal into 3 parts for the regressions) it became clear that some of the variable had zero or almost zero impact on ERA when isolated. These included some that I assumed beforehand — like breaking ball percentage thrown and changeup percentage thrown — but also more interesting discoveries, including command and ability to change speeds. Here are the plots:

 

Both of these highly touted old-school skills failed the correlation test, having a basically 0 correlation coefficients and flat slopes, meaning as they get better ERA doesn’t follow suit. This might have to do partially with sampling bias as only data from the last two season of Statcast is publicly available. This limits my sample to the current game, which has trended away from maximizing these skills. Even so, this level of separation from ERA is very noteworthy and should be taken into account. The data is not saying these skills are not entirely unimportant, as they are good auxiliary skills, but just that they alone aren’t enough to drive success.

Next, I will delve into what skills my analysis found most predictive of MLB success. These were, as new school advocates already are aware of, fastball velocity and fastball spin rate, followed by slider spin.

Each of these skills still may seem to have a small R^2 at .08, .078, and .023 respectively but when isolating a single trait, the first two are about as good as you can ask for. Just like you wouldn’t have a shot at telling me a player’s ERA if you just knew he threw 93 MPH, the computer can’t really tell, either. But the computer does have a better shot at it with those two skills than any other I measured, by a wide margin. Another important finding about these three skills is that they each have relatively steep negative slopes meaning as they increase, ERA will fall with them. Velocity and spin rate have been buzz words in baseball for years now and this is just more backing for them to gain further influence in the future.

Now that we’ve gotten through the breakdown of methodology and explanation of my backing, here’s the ranking of each skill, from most important to least important based on their correlation and slope:

1. Fastball Spin Rate (pushed ahead by a slightly steeper slope)
2. Fastball Velocity
3. Slider Spin Rate
4. Fastball Percentage Thrown
5. Curveball Spin Rate
6. Command
7. Fastball-Changeup Velocity Delta
8. Breaking Ball Percentage Thrown
9. Changeup Percentage Thrown

It’s worth noting that after Slider Spin Rate all other variables have basically a zero effect by themselves.

As you can probably tell from the individual skills analysis, old school seems to be at a clear disadvantage. But as they always like to preach, it’s the total package that makes a player. To account for this, I used the new/old skill groupings listed above and ran multiple linear regressions for each. This basically means the computer took into account each group’s variables together and measured the relationship between them and ERA. The results were well, not that surprising: Old school got crushed again. The correlation coefficient for the Old school group was relatively tiny for multiple variables, .024, about the same as just slider spin rate. The predicted value scatter plot also shows this as the computer had no idea how to place anything and just threw everything around the mean to hedge its losses.

The new school group fared much better, having a pretty strong correlation, all things considered, at .115. The plot also showed this with a more accurate, spread out distribution and less severe errors.

The combination of the individual skill evaluations and the groups clearly show that the new-school training regimes are focusing on the more data-backed skills. This finding is no surprise as one of their main selling points is embracing data and implementing it in a useful way. While this work does show the success of these traits in the MLB, what it doesn’t take into account is whether these skills can be taught and whether they contribute to increased injury risk, two big complaints from skeptics. These might be covered in later pieces but I thought them important to mention here as well.

This analysis may seem to completely write off the skills of command, changing speeds, and mixing your pitches that old school baseball loves to glorify. But these skills absolutely have their place. As secondary skills, they are needed along with the other abilities but in general, they can’t hold by themselves. Maybe some guys can get by with just location and changing speeds, but if you are forced to choose one of the two sets of skills, the data shows you should pick new school.

Fastball velocity and pitch spin have been the main drivers of success. If you can’t hit the broad side of the barn with your pitches, they’re obviously a moot point. But studies like mine have repeatedly shown they are crucial to pitching in today’s game so they should be a focus of player development.