<p>I don't know the answer but according to UCSB's website, only 2% of the students are from other states (another 2% are international and 1% unknown). The higher-end the UC it seems the more OOS applicants. </p>
<p>I checked UCR's and UCSB's websites. UCR states it gives not relevance to OOS or IS. UCSB weights them the same but seems to have a cutoff for OOS (as ebeee stated). UCLA does give priority to in-state so I assume the requirements for OOS are higher than for IS. The following is from UCLA's website:
[quote]
While, as a state funded public institution, UCLA gives priority to applicants who are California residents, we also admit hundreds of other students from all over the country. Since UCLA receives a large number of applications (from both in-state and out), admission is highly selective and far exceeds the University of California's minimum eligibility requirements for out-of-state applicants.
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<p>The reasons for the low OOS numbers may not be due simply to admissions decisions, it's likely due in part to lack of applicants. The UCs are more expensive for OOS and due to that, many OOS students will simply either pick a state college in-state, a state U that doesn't charge such a high premium for OOS, or a private. </p>
<p>If you're interested and are willing to pay the tuition, then go ahead an apply.</p>