Every University of California campus publishes the same kind of data -- freshman admit rate broken out by broad academic discipline, updated every year, straight from the UC Office of the President's own Freshman Admission by Discipline dashboard. Line up several campuses side by side, using their raw applicant and admit counts rather than already-rounded headline percentages, and a real pattern emerges: how much harder a competitive major is than its own campus's overall rate isn't a fixed amount. It scales with how selective the campus already is.
The pattern, in one chart
The chart above lines up seven examples across five UC campuses, ranked by how many times harder each competitive major is than its own campus's overall rate. At UC Merced -- an admissions-open campus with a 94% overall admit rate -- every discipline sits between 91% and 97%. There's essentially no gap between the campus's hardest major (Arts & Humanities, at 91%) and its easiest (Engineering, at 97%): a 1.04x difference, functionally noise. At UC Riverside (87% overall), the gap widens slightly -- Computer Science, at 81%, is about 1.07x harder than the campus average. At UC Berkeley (11% overall), the gap becomes real: Public Health admits at 2%, roughly 5.2x harder than Berkeley's own average. And at the two most selective UC campuses, the gap becomes extreme: UCLA's Nursing major is roughly 17x harder than UCLA's own overall rate, and UC Irvine's Nursing major is roughly 36x harder than UC Irvine's.
Why the math has to be done on raw counts, not rounded percentages
This is worth being explicit about, because it's the difference between a real finding and an artifact of rounding. UC's dashboard displays whole-percent figures -- UCLA Nursing shows as "1%," UCLA overall shows as "9%." Dividing those rounded figures gives 9x, which understates the real gap. The actual counts are 31 admits out of 5,668 Nursing applicants (0.55%) against 13,659 admits out of 145,060 applicants campus-wide (9.42%) -- a 17.2x gap, not 9x. The same issue is even larger at UC Irvine, where the rounded math (1% vs. 29%) suggests a 29x gap, but the real applicant and admit counts (57 of 7,079, against 35,658 of 124,223) work out to 35.7x. Whenever you're comparing a small percentage to a larger one, ask for -- or calculate from -- the underlying counts before trusting the ratio.
Why the gap scales with campus selectivity
The mechanism is straightforward once you see it laid out: a highly selective campus already has far more qualified applicants than seats, campus-wide. Layer a capacity-constrained major on top of that -- one where the number of faculty, lab stations, or clinical placements is fixed regardless of how large the applicant pool grows -- and the two constraints compound. At an open-access campus like Merced, there's enough capacity across the board that even a "competitive" major doesn't have to turn away many qualified applicants. At Irvine or UCLA, the campus is already turning away the large majority of applicants before you even get to a major with its own separate capacity ceiling, like Nursing's fixed number of clinical training slots.
What this means for you
- The same major can carry a completely different real difficulty at different UC campuses. Nursing at UC Merced isn't offered as a capacity-constrained freshman major the way it is at UCLA and UC Irvine -- always check the specific campus's own by-major data, not a generic "how hard is this major" assumption.
- A school's overall admit rate tells you almost nothing about a specific competitive major's real odds, and the gap gets worse exactly where the school is already selective. The more competitive the campus overall, the more skeptical you should be of using its headline rate as a stand-in for your target major's actual rate.
- When you see a ratio built from two rounded percentages, redo the math from the real counts if you can find them. A "9x" gap and a genuine "17x" gap look similar at a glance but represent very different realities.
- This same logic applies well beyond the UC system -- see our piece on why engineering and CS admissions can be far more competitive than a university's headline number suggests for the same mechanism at Berkeley, Carnegie Mellon, and elsewhere.
- If you're new to the UC system, its application mechanics differ enough from the rest of the country to trip up an otherwise strong applicant -- see how UC admissions actually works for the filing period, PIQs, and A-G requirements behind the numbers in this piece.