Relative Selectivity by U.S. News "Selectivity rank"

Composite factors stated as standardized scoring (65%), top 10 percent within HS class (25%) and acceptance rate (10%).

LACs

  1. Pomona
  2. Harvey Mudd
  3. Haverford
  4. Williams
  5. Amherst
  6. Swarthmore
  7. Bowdoin
  8. Washington & Lee
  9. Middlebury
  10. Grinnell
  11. Wellesley
  12. Hamilton
  13. Barnard
  14. Carleton
  15. Vassar
  16. Davidson
  17. Colgate
  18. Scripps
  19. Wesleyan
  20. Colorado College

(Claremont McKenna appears to be in error at 21. With proper placement, the school would affect the above figures as well.)

Universities

  1. UChicago
  2. Caltech
  3. Yale
  4. MIT
  5. Princeton
  6. Harvard
  7. Columbia
  8. Stanford
  9. UPenn
  10. Johns Hopkins
  11. Brown
  12. Vanderbilt
  13. Duke
  14. Dartmouth
  15. Northwestern
  16. Rice
  17. WUStL
  18. Notre Dame
  19. Tufts
  20. Cornell
  21. UC-Berkeley

As with the LACs, one or more statistically questionable placements may have occurred.

Was this calculated by US News itself? I’d have thought Harvey Mudd to rank higher than Pomona

Yes, those figures were calculated by the publication.

By standardized scoring in isolation, HMC appears as a stratospheric seventh in the nation:

http://www.businessinsider.com/smartest-colleges-in-america-2015-9

Why is standardized testing given 65% weight in this selectivity rating when it is unlikely that standardized testing is weighted that heavily by any of the super-selective or highly selective schools in question?

From which perspective are you looking at this? An individual applicant cannot have an “acceptance rate,” for example?

But to partially address your question, USNWR decided on these proportions because they found that the declining reporting of HS rank diminished the importance of that component.