2015 MLB Relative Power Index (RPI) as of the games of April 13,2015 from ESPN.GO.COM

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	Kansas City Royals	.711	7	0	1.000	.615	2	52	18	6-1	.893
2	Chicago Cubs	.703	4	2	.667	.715	22	25	24	3-3	.520
3	Atlanta Braves	.620	6	1	.857	.541	14	32	15	6-1	.820
4	Colorado Rockies	.604	5	2	.714	.567	11	37	22	5-2	.739
5	St. Louis Cardinals	.602	3	3	.500	.636	4	22	18	4-2	.599
6	Los Angeles Angels	.587	3	4	.429	.640	10	22	29	3-4	.365
7	Detroit Tigers	.564	6	1	.857	.466	1	51	21	6-1	.855
8	New York Mets	.564	4	3	.571	.561	18	22	19	4-3	.573
9	Cincinnati Reds	.554	4	3	.571	.548	7	30	30	4-4	.500
10	Boston Red Sox	.550	5	2	.714	.495	3	43	33	4-3	.629
11	New York Yankees	.536	3	4	.429	.572	26	37	38	3-4	.487
12	Los Angeles Dodgers	.536	4	3	.571	.524	8	32	33	3-4	.485
13	Toronto Blue Jays	.528	4	3	.571	.513	5	39	29	5-2	.644
14	Arizona Diamondbacks	.516	4	3	.571	.497	21	35	30	4-3	.576
15	San Diego Padres	.502	4	4	.500	.503	16	35	31	4-4	.560
16	Baltimore Orioles	.496	3	4	.429	.518	6	36	38	3-4	.473
17	Cleveland Indians	.480	2	4	.333	.529	17	22	28	2-4	.382
18	Philadelphia Phillies	.474	3	4	.429	.490	20	16	25	2-5	.291
19	Chicago White Sox	.470	2	4	.333	.516	24	18	33	1-5	.229
20	San Francisco Giants	.464	3	5	.375	.494	15	23	32	3-5	.341
21	Seattle Mariners	.450	3	4	.429	.457	12	25	37	2-5	.313
22	Miami Marlins	.428	1	6	.143	.523	23	20	38	2-5	.217
23	Washington Nationals	.415	2	5	.286	.459	9	17	29	2-5	.256
24	Pittsburgh Pirates	.404	3	4	.429	.396	19	29	27	4-3	.536
25	Milwaukee Brewers	.397	2	5	.286	.434	29	21	40	2-5	.216
26	Minnesota Twins	.391	1	6	.143	.474	30	16	45	1-6	.112
27	Tampa Bay Rays	.388	4	3	.571	.327	28	30	28	4-3	.534
28	Texas Rangers	.365	3	5	.375	.362	27	27	39	3-5	.324
29	Oakland Athletics	.362	4	4	.500	.316	13	51	27	6-2	.781
30	Houston Astros	.342	3	4	.429	.313	25	17	26	2-5	.299

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.