Which school is better in terms of finding a job, Cal Poly SLO or UC Irvine?

I want to major in either Informatics with Human computer interaction at UCI or Business Adminisration with a emphasis in information systems at Cal Poly SLO.

Both. It is not as much about which school you attend but more about the resources and opportunities you take advantage of while you are there. Most employers are more interested in your job skill set than the name of the school. In the end, getting a job will be up to you. Also the first hurdle is getting an acceptance for either school, which is not an easy task.

I don’t see a clear advantage to one or the other, either.

agree - both are excellent but, both are very competitive. Step one - get into both, step 2 pick one, step 3 make the most of what’s there via internships, clubs, leadership roles etc. step 4 walk into your life-long dream job at 22 years old. none of the steps is quite that easy. Let’s start with step one - what are your qualifications?