2015 MLB Relative Power Index (RPI),as of the games of May 5,2015 from ESPN.GO.COM

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	New York Yankees	.567	17	10	.630	.546	7	131	99	17-10	.636
2	St. Louis Cardinals	.552	20	6	.769	.480	1	116	72	19-7	.722
3	Detroit Tigers	.552	17	10	.630	.526	4	119	112	14-13	.530
4	New York Mets	.536	17	10	.630	.504	6	104	85	16-11	.600
5	Kansas City Royals	.533	17	9	.654	.492	2	133	86	18-8	.705
6	Los Angeles Dodgers	.529	17	9	.654	.487	5	126	87	18-8	.677
7	San Diego Padres	.524	14	14	.500	.532	10	131	127	14-14	.516
8	Tampa Bay Rays	.519	14	13	.519	.519	9	96	97	13-14	.495
9	Minnesota Twins	.514	14	13	.519	.512	21	114	115	13-14	.496
10	Chicago Cubs	.512	13	12	.520	.509	8	107	105	13-12	.509
11	Houston Astros	.509	18	9	.667	.457	3	127	97	17-10	.632
12	Baltimore Orioles	.506	12	12	.500	.508	14	122	111	13-11	.547
13	San Francisco Giants	.502	14	13	.519	.497	18	87	100	12-15	.431
14	Boston Red Sox	.500	13	14	.481	.507	13	125	139	12-15	.447
15	Washington Nationals	.499	13	15	.464	.510	15	112	117	13-15	.478
16	Cincinnati Reds	.498	13	13	.500	.497	20	107	109	13-13	.491
17	Toronto Blue Jays	.495	13	15	.464	.506	17	150	145	14-14	.517
18	Atlanta Braves	.489	13	14	.481	.491	24	118	119	13-14	.496
19	Miami Marlins	.489	13	14	.481	.491	12	116	103	15-12	.559
20	Arizona Diamondbacks	.487	10	14	.417	.511	25	100	101	12-12	.495
21	Pittsburgh Pirates	.486	12	14	.462	.494	11	94	85	14-12	.550
22	Chicago White Sox	.484	9	14	.391	.515	27	75	110	7-16	.317
23	Colorado Rockies	.482	11	13	.458	.490	19	99	131	9-15	.364
24	Cleveland Indians	.478	9	16	.360	.517	26	105	125	10-15	.414
25	Seattle Mariners	.468	11	16	.407	.489	22	99	125	10-17	.385
26	Philadelphia Phillies	.468	10	18	.357	.505	29	77	133	7-21	.251
27	Oakland Athletics	.463	12	16	.429	.475	23	140	122	16-12	.568
28	Los Angeles Angels	.463	12	15	.444	.469	16	102	108	13-14	.471
29	Milwaukee Brewers	.454	8	19	.296	.507	30	88	134	8-19	.301
30	Texas Rangers	.430	10	16	.385	.445	28	98	119	11-15	.404

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.