How large of a bearing does undergrad have on med school admissions and becoming a physician?

I know a lot of people on this site are obsessed with getting into T-10 schools and so am I, but statistically speaking the majority of us obviously aren’t going to make it into Harvard or Stanford for undergrad. I know that undergrad is very important for business/engineering etc but as long as you go to a decently reputable school (mid tier ivies like UCSB, UCSD, etc) that has a good premed program and you do well on the MCAT as well as get research experience, how important REALLY is undergrad for med school specifically and becoming a doctor in the future? (neurosurgery candidate here) I can see med school being important but even that doesn’t seem huge - once you’re an MD, you’re an MD…

Med school admissions are based upon the achievements of the individual-- GPA/sGPA, MCAT, LORs, having the appropriate pre-med ECs, strong oral & written communication, strong interpersonal skills, interview skills, etc—not where you attended undergrad.

On p. 14 of this document–

There is chart of what factors Admissions Deans view as being important when deciding who to invite for an interview and who to admit. The selectivity of an applicant’s undergrad is ranked as being among the least important factors considered.

A student can attend just about any college in the US and still be successful applicant to med school. Successful applicants can even begin their college education at community college. Look at the incoming classs at just about any med school (including “prestige” programs) and you’ll see matriculants from dozens and dozens of different undergrads.

BTW, research is highly over-valued by most pre-meds. Adcomms rank having research as being of only medium importance. Clinical experiences, non-medical community service physician shadowing and leadership are all ranked as being significantly more important by adcomms.

P.S. Word of advice—it’s way, way way too soon to start picking out specialties. You need to first:
a) get into college
b) get into med school

BTW, you're wrong about the importance of going to "name" undergrad for engineering. The most important factor for engineers is not what college you attend , but whether the engineering program is ABET-accredited. 

Undergraduate is very important . You MCAT score, cause load, GPA, extracurriculars, volunteerism, and clinical experience will be very important. However, it sounds like you are asking about the school that you attend and if medical schools look at schools differently (IVY vs state school) and for the most part no. Pick a school that has the class size, support and extracurriculars you want. Ultimately, you need to be happy and successful (in terms of academics). You’ll be there for four years, so you want to live in a place you like at a school where you feel supported. That is much more important than whether your school is a well known name. Medical schools do not give “extra credit” to people who went to prestigious schools. Ultimately, admissions committees care about gpa, mcat and extracurriculars.

Directly: very little. The algorithm that makes the first cut doesn’t even include it as a criterion. Even as a soft factor, college name or ranking is low.

However undergrad experience is paramount: can you be among the top students in every class you take? What support do they offer? How large e small, cutthroat or collaborative are the classes? How well do you get to know your professors? Do you have a personal adviser right off the bat? Do they have volunteer opportunities set up? How easy is it to get to a community clinic that serves the homeless, non English speakers, etc?
Choosing a college where medically-related experiences are common, the system supportive, and the students collaborative, is one of the most important factors. The main factor of course, is yourself.

Finally, remember that the vast majority of would be premeds in high school never make it to Mee school for various reasons. As a result, choose a college for itself because it’s a good fit and a good value.

BTW, UCSD has had problems with their premeds. They’re trying to fix it. But right now the best program among UC’s is UCR and it’s various special programs. UCD is strong too.
Also, don’t discount LACs, especially those in the Midwest. Coming from California will actually be a plus for you there.
Start reading the Fiske guide.

I think it depends on what type of medical school you want to attend. Some med schools are trying to create the next great academic researchers. Some are trying to create community doctors for their state. It just depends on their mission.

In you want to be in academic medicine, or you want a research intensive/selective specialty, then where you go to med school matters a bit, and for those types of med schools, where you went to undergrad matters a bit. Bear in mind, I’m not saying it’s the most important thing in the world, but you’ll find very few academic neurosurgeons that went from a community college, into a directional state university to launch their careers.

You might, however, see community surgeons that have taken the state school route.

So I guess I would answer, in my opinion, that some medical schools do care about the prestige of your undergrad institution and some don’t care that much. It all depends on the mission of the medical school. State medical schools are less likely to care about the prestige of your undergrad institution.