2015 MLB Relative Power Index (RPI),as of the games of August 18,2015

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	St. Louis Cardinals	.538	76	43	.639	.505	1	468	346	77-42	.647
2	Kansas City Royals	.534	72	46	.610	.508	2	516	437	69-49	.582
3	Pittsburgh Pirates	.526	70	47	.598	.502	3	501	433	67-50	.572
4	Chicago Cubs	.522	67	50	.573	.505	4	471	441	62-55	.533
5	New York Yankees	.515	66	52	.559	.501	5	567	499	66-52	.564
6	Toronto Blue Jays	.513	66	54	.550	.501	6	630	489	75-45	.624
7	Los Angeles Dodgers	.510	67	52	.563	.492	7	500	440	67-52	.564
8	Houston Astros	.509	65	55	.542	.498	9	520	445	69-51	.577
9	New York Mets	.506	64	55	.538	.495	8	443	419	63-56	.528
10	Los Angeles Angels	.506	62	57	.521	.501	12	486	457	63-56	.531
11	Detroit Tigers	.505	57	61	.483	.512	18	520	570	54-64	.454
12	Minnesota Twins	.503	59	60	.496	.506	17	504	533	56-63	.472
13	San Francisco Giants	.503	65	54	.546	.488	10	519	450	68-51	.571
14	Texas Rangers	.502	60	58	.508	.500	14	530	560	56-62	.472
15	Baltimore Orioles	.502	61	57	.517	.497	11	529	460	67-51	.569
16	Chicago White Sox	.502	55	62	.470	.512	21	437	505	50-67	.428
17	Tampa Bay Rays	.499	59	60	.496	.500	15	448	458	58-61	.489
18	Cleveland Indians	.495	55	63	.466	.505	20	472	496	56-62	.475
19	Washington Nationals	.495	59	59	.500	.493	13	494	477	61-57	.518
20	San Diego Padres	.495	58	62	.483	.498	19	482	529	54-66	.454
21	Seattle Mariners	.493	56	64	.467	.502	24	457	536	51-69	.421
22	Arizona Diamondbacks	.493	58	60	.492	.493	16	537	506	63-55	.530
23	Cincinnati Reds	.489	51	66	.436	.507	23	458	508	52-65	.448
24	Milwaukee Brewers	.488	51	70	.421	.510	26	471	536	53-68	.436
25	Oakland Athletics	.487	52	69	.430	.506	27	488	484	61-60	.504
26	Boston Red Sox	.486	53	66	.445	.499	25	538	587	54-65	.457
27	Atlanta Braves	.476	53	66	.445	.486	22	439	526	49-70	.411
28	Colorado Rockies	.474	48	69	.410	.495	29	525	621	49-68	.417
29	Miami Marlins	.472	49	70	.412	.492	30	443	489	54-65	.451
30	Philadelphia Phillies	.466	46	73	.387	.492	28	438	594	42-77	.352

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.