2015 MLB Relative Power Index (RPI),as of the games of May 2,2015 from ESPN.GO.COM

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	New York Yankees	.584	15	9	.625	.570	7	116	88	15-9	.635
2	Detroit Tigers	.557	16	9	.640	.529	4	111	103	13-12	.537
3	Tampa Bay Rays	.539	13	11	.542	.538	14	89	90	12-12	.494
4	San Diego Padres	.538	13	12	.520	.544	8	123	113	14-11	.542
5	New York Mets	.538	16	9	.640	.504	2	101	82	15-10	.603
6	Chicago Cubs	.536	13	9	.591	.517	10	91	83	12-10	.546
7	Los Angeles Dodgers	.534	15	8	.652	.495	5	114	81	15-8	.665
8	Kansas City Royals	.529	16	8	.667	.483	1	124	77	17-7	.722
9	St. Louis Cardinals	.527	17	6	.739	.456	3	96	57	17-6	.739
10	Houston Astros	.523	17	7	.708	.461	12	118	82	16-8	.674
11	Minnesota Twins	.513	12	12	.500	.518	27	92	103	11-13	.444
12	Baltimore Orioles	.510	11	11	.500	.513	17	116	106	12-10	.545
13	Boston Red Sox	.503	12	12	.500	.504	6	117	126	11-13	.463
14	Pittsburgh Pirates	.502	12	12	.500	.502	9	91	75	14-10	.595
15	Toronto Blue Jays	.500	12	13	.480	.507	11	137	128	13-12	.534
16	San Francisco Giants	.491	11	13	.458	.502	22	74	100	8-16	.354
17	Cincinnati Reds	.491	12	12	.500	.488	20	100	103	12-12	.485
18	Colorado Rockies	.491	11	12	.478	.495	13	93	123	8-15	.364
19	Miami Marlins	.490	12	12	.500	.486	23	108	90	14-10	.590
20	Atlanta Braves	.490	11	13	.458	.500	19	102	114	11-13	.445
21	Arizona Diamondbacks	.484	10	13	.435	.501	24	100	100	12-12	.500
22	Washington Nationals	.481	11	14	.440	.495	16	104	111	12-13	.467
23	Chicago White Sox	.478	8	13	.381	.510	26	67	95	7-14	.332
24	Cleveland Indians	.476	8	15	.348	.518	25	92	113	9-14	.399
25	Seattle Mariners	.472	10	14	.417	.491	21	86	111	9-15	.375
26	Los Angeles Angels	.458	11	13	.458	.458	15	95	96	12-12	.495
27	Oakland Athletics	.454	10	15	.400	.473	18	124	112	14-11	.551
28	Philadelphia Phillies	.449	8	17	.320	.492	29	66	120	6-19	.232
29	Milwaukee Brewers	.437	6	18	.250	.499	30	77	120	7-17	.292
30	Texas Rangers	.407	8	15	.348	.427	28	88	110	9-14	.390

Glossary

• W: Wins
• L: Losses
• PCT: Winning percentage
• RPI: Relative Power Index+
• SOS: Strength of schedule

• PWR: ESPN Power Ranking
• RS: Runs scored
• RA: Runs allowed
• EXW-L: Expected W-L*
• EXWP: Expected winning percentage*

+The basic formula is 25% team winning percentage, 50% opponents' average winning percentage, and 25% opponents' opponents' average winning percentage.
*ExW-L and ExWP are derived from Bill James' Pythagorean theorem of baseball: Runs scored [squared] / (Runs scored [squared] + runs allowed [squared]). This formula was designed to relate a team's runs scored and runs allowed to its won-lost record.