Mantle, Mays, Aaron Righty/Lefty splits don't add up.

This was originally intended as a normal comparison of the three players but more was added to show that, even for great post WWII players, there is data missing.

This link contains their data. The most relevant is repeated below. The splits and career data is simply copied from Baseball Reference. Below that I did the split sum and split difference.

Mantle	Split	G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	TB
Mantle	vs RHP	1,979	6,613	5,297	1,112	1,492	207	42	373	1,012	124	30	1,263	1,264	.282	.419	.548	.967	2,902
Mantle	vs LHP	1,206	3,253	2,771	557	913	136	28	163	494	28	10	462	447	.330	.424	.575	.999	1,594
Mays	Split	G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	TB
Mays	vs RHP	2,510	8,806	7,794	1,412	2,338	370	93	448	1,361	253	68	913	1,117	.300	.373	.544	.917	4,238
Mays	vs LHP	1,291	3,533	2,947	618	900	145	43	207	522	74	33	538	400	.305	.412	.595	1.006	1,752
Aaron	Split	G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	TB
Aaron	vs RHP	2,844	10,121	9,073	1,553	2,718	434	73	527	1,665	211	63	921	1,076	.300	.362	.538	.900	4,879
Aaron	vs LHP	1,384	3,584	3,079	581	980	174	23	220	594	25	10	459	282	.318	.405	.604	1.009	1,860
		G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	TB
Mantle	career	2,401	9,907	8,101	1,675	2,415	344	72	536	1,509	153	40	1,733	1,718	.298	.421	.557	.977	4,511
Mays	career	2,992	12,496	10,881	2,060	3,283	523	140	660	1,903	338	102	1,467	1,527	.302	.384	.558	.942	6,066
Aaron	career	3,298	13,941	12,364	2,175	3,771	624	98	755	2,297	240	73	1,403	1,381	.305	.374	.555	.929	6,856
		G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	TB
Mantle	Split Sum		9,866	8,068	1,669	2,405	343	70	536	1,506	152	40	1,725	1,711	.298		.557		4,496
Mays	Split Sum		12,339	10,741	2,030	3,238	515	136	655	1,883	327	101	1,451	1,517	.301		.558		5,990
Aaron	Split Sum		13,705	12,152	2,134	3,698	608	96	747	2,259	236	73	1,380	1,358	.304		.555		6,739
		G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	TB
Mantle	Split Dif		-41	-33	-6	-10	-1	-2	0	-3	-1	0	-8	-7	.00009		.00026		-15
Mays	Split Dif		-157	-140	-30	-45	-8	-4	-5	-20	-11	-1	-16	-10	-.00054		-.00032		-76
Aaron	Split Dif		-236	-212	-41	-73	-16	-2	-8	-38	-4	0	-23	-23	-.00069		-.00044		-117

Look at Home Runs. Mantle's splits add up but Mays and Aaron are off by 5 and 8 respectively.

Games are not added because they batted both (vs RHP) and (vs LHP) in many games.

I didn't try to do OBP (On Base Percentage - really average) because it gets a little hairy with no Sacrifice Flies (SF) before 1954. This also negates OPS (On base Plus Slugging).

I'm working on Righty/Lefty splits for batters with at least 250 HR (vs RHP) and at least 100 HR (vs LHP). There will be discrepancies. How should they be handled? For instance, Mantle's HR add up but his AB do not. That impacts his AB/HR rate. Not much but some. Most of the careers of Mantle, Mays and Aaron have full data. But for Babe Ruth, whose entire career has play by play data missing, his HR splits are 488+210=698. Not 714. The Babe has 12 homers missing. See:

https://www.baseball-reference.com/players/split.fcgi?id=ruthba01&year=Career&t=b 

Data Coverage: https://www.baseball-reference.com/about/coverage.shtml

The end.