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

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	St. Louis Cardinals	.541	73	41	.640	.508	1	453	334	74-40	.648
2	Kansas City Royals	.531	68	46	.596	.509	2	496	428	65-49	.573
3	Chicago Cubs	.524	65	48	.575	.507	5	450	420	60-53	.534
4	Pittsburgh Pirates	.524	66	46	.589	.502	3	475	415	64-48	.567
5	Toronto Blue Jays	.513	64	52	.552	.500	6	615	475	73-43	.626
6	New York Yankees	.512	62	51	.549	.500	8	542	481	63-50	.559
7	Los Angeles Dodgers	.509	64	51	.557	.493	4	481	428	64-51	.558
8	Houston Astros	.508	62	53	.539	.498	10	502	424	67-48	.584
9	New York Mets	.508	63	52	.548	.494	7	432	400	62-53	.538
10	Los Angeles Angels	.505	60	54	.526	.499	11	471	436	61-53	.539
11	Minnesota Twins	.504	57	57	.500	.506	15	484	509	54-60	.475
12	Detroit Tigers	.504	55	59	.482	.511	17	500	549	52-62	.453
13	Chicago White Sox	.503	54	58	.482	.510	19	422	485	48-64	.431
14	Tampa Bay Rays	.501	58	56	.509	.499	16	427	431	56-58	.495
15	Baltimore Orioles	.500	57	56	.504	.498	13	492	442	63-50	.553
16	Texas Rangers	.499	56	57	.496	.500	14	502	544	52-61	.460
17	San Francisco Giants	.498	61	53	.535	.486	9	491	437	64-50	.558
18	Washington Nationals	.498	58	56	.509	.494	12	468	446	60-54	.524
19	Cleveland Indians	.497	53	60	.469	.507	20	455	476	54-59	.477
20	Seattle Mariners	.494	54	61	.470	.502	22	430	485	51-64	.440
21	Arizona Diamondbacks	.493	56	57	.496	.492	18	514	487	60-53	.527
22	San Diego Padres	.492	54	61	.470	.500	23	452	511	50-65	.439
23	Cincinnati Reds	.492	51	62	.451	.505	24	450	490	52-61	.458
24	Milwaukee Brewers	.489	48	68	.414	.514	28	450	517	50-66	.431
25	Oakland Athletics	.488	51	65	.440	.504	25	470	446	61-55	.526
26	Boston Red Sox	.484	50	64	.439	.499	26	482	557	49-65	.428
27	Atlanta Braves	.477	51	63	.447	.487	21	427	501	48-66	.421
28	Colorado Rockies	.475	47	66	.416	.495	27	504	590	48-65	.422
29	Philadelphia Phillies	.471	46	69	.400	.494	29	429	573	41-74	.359
30	Miami Marlins	.469	46	68	.404	.491	30	419	468	51-63	.445

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.