For the third straight week, the Pac-10 sits atop the ESPN softball conference power rankings. The Pac-10 increased its number of teams in the RPI's top 10 from three to four this week thanks to No. 7 California moving up four spots. Its lowest-ranked team, No. 85 Oregon State, would be the highest ranked team in nine other conferences.

The Big East, the worst of the BCS conferences through the first four weeks, saw its ranking drop five points from last week. Its 106.4615 average is its lowest of the season, even with Notre Dame and Louisville remaining in the RPI's top 25.

Conference USA, the best non-BCS conference to date, has had five teams in the RPI's top 50 each of the last three weeks. The SWAC extended its four-week streak of being the lowest-ranked conference.

Conference (RPI Average)

1. Pac-10 (21.625)
2. Big 12 (23.4)
3. SEC (47.2727)
4. Big Ten (56.6364)
5. ACC (67.5)
6. C-USA (81.4444)
7. Sun Belt (89.1111)
8. MWC (96.6667)
9. Big East (106.4615)
10. Big West (112.25)
11. A-Sun (127.3636)
12. WAC (130.625)
13. MVC (135.2)
14. Southland (138.5455)
15. MAC (147.75)
16. Horizon (147.7778)
17. Southern (152.4444)
18. Ohio Valley (165.3636)
19. Big South (167.5714)
20. A-10 (168.8182)
21. Colonial (176.5)
22. A-East (181.5714)
23. Ivy (195.25)
24. Summit (196.1111)
25. Northeast (198.4545)
26. P-Coast (218.25)
27. Patriot (223)
28. MEAC (248.9091)
29. SWAC (265.2)