2015 MLB Relative Power Index (RPI),as of the games of May 13,2015

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	Detroit Tigers	.550	20	14	.588	.538	4	142	140	17-17	.507
2	New York Yankees	.548	21	14	.600	.530	6	164	131	21-14	.610
3	St. Louis Cardinals	.545	23	10	.697	.495	1	150	100	23-10	.692
4	Kansas City Royals	.533	21	13	.618	.505	2	167	128	21-13	.630
5	Los Angeles Dodgers	.526	22	11	.667	.480	3	174	112	23-10	.707
6	Minnesota Twins	.518	19	15	.559	.505	12	158	139	19-15	.564
7	Tampa Bay Rays	.518	19	16	.543	.509	9	133	126	18-17	.527
8	Chicago Cubs	.516	18	15	.545	.507	13	139	141	16-17	.493
9	New York Mets	.515	20	14	.588	.491	7	125	107	20-14	.577
10	Houston Astros	.509	21	13	.618	.473	5	145	131	19-15	.551
11	San Diego Padres	.508	18	17	.514	.506	11	161	163	17-18	.494
12	Pittsburgh Pirates	.504	17	17	.500	.505	19	130	114	19-15	.565
13	Baltimore Orioles	.502	15	17	.469	.513	16	151	146	17-15	.517
14	Washington Nationals	.501	19	16	.543	.487	8	167	155	19-16	.537
15	San Francisco Giants	.499	17	17	.500	.498	18	112	129	15-19	.430
16	Toronto Blue Jays	.498	17	18	.486	.502	10	185	166	19-16	.554
17	Chicago White Sox	.497	14	17	.452	.513	26	114	149	11-20	.369
18	Cincinnati Reds	.497	17	17	.500	.496	15	137	138	17-17	.496
19	Arizona Diamondbacks	.494	15	18	.455	.507	23	161	148	18-15	.542
20	Cleveland Indians	.493	12	20	.375	.533	27	139	161	14-18	.427
21	Los Angeles Angels	.488	17	17	.500	.483	14	125	124	17-17	.504
22	Boston Red Sox	.486	16	18	.471	.492	21	144	174	14-20	.406
23	Seattle Mariners	.486	15	18	.455	.496	24	130	145	15-18	.446
24	Miami Marlins	.485	16	19	.457	.495	17	145	143	18-17	.507
25	Texas Rangers	.473	15	19	.441	.483	25	139	153	15-19	.452
26	Milwaukee Brewers	.472	12	23	.343	.515	30	133	179	12-23	.356
27	Atlanta Braves	.468	15	19	.441	.477	20	143	156	16-18	.457
28	Colorado Rockies	.462	11	19	.367	.493	28	116	167	10-20	.325
29	Philadelphia Phillies	.459	12	23	.343	.497	29	99	164	9-26	.267
30	Oakland Athletics	.457	13	23	.361	.489	22	166	165	18-18	.503

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.