From my viewpoint, this is completely dependent on what you need at each step in your educational and professional careers.
On beginning undergrad, I had narrowed down my choices between going to the University of Miami (11,380 undergrads in 2015) vs. Mercer University (4,419 undergrads in 2015). Since Mercer was the only school I had visited, I decided to go there.
After graduation, I was faced with a similar decision size-wise for graduate school – to go to University of Texas – Austin (52,059 total enrollment in 2015) vs. Emory University (14,769 total enrollment in 2014). Emory University aligned more with my desired trajectory, and I chose to matriculate there.
Subsequently, I have worked at the U.S. Environmental Protection Agency, Emory University, and now the Centers for Disease Control and Prevention; all have 14K+ employees and can be considered the equivalent of large corporations. Whether you attend a large/small school or work at a large/small business, there are advantages and disadvantages to each.
At Mercer, I definitely benefited from the small class sizes that resulted in actually knowing my professors. More so, all of my classes, including my larger science classes, were taught by professors rather than teaching assistants.
Since the school was small, and the chemistry department a microcosm of it, there was less competition and more emphasis on learning. Due to the size, even extracurricular activities allowed many of us to take on leadership roles and impact our local campus community in more meaningful ways.
This lead to a better sense of community.
The cafeteria lines were also much shorter. However, there were a few drawbacks from attending a smaller school. For example, there was less variety in terms of class offerings and times. As a double major in Spanish language and chemistry, I found myself choosing the science offering that semester, and delaying my Spanish classes for later semesters. There was also less grant funding in our science department. At the time of matriculation, Mercer had no major sports teams but has since started a football team that has increased school spirit dramatically. Finally, there is a lack of privacy that comes along with being a part of any small community.
While at Emory, I enjoyed many of the benefits of being in graduate school in a smaller department with the added benefit of not only internal but external grant funding. Again, as part of a smaller department at a larger institution, you are in a small-scale version of the whole. This is ideal in the sense that it is a small school environment backed by a big parent.
At this point school size became irrelevant to me, and I turned my focus towards expanding my network. In my experience, the size of your network matters little compared to the quality of persons in your network. Do you have solid mentors, sponsors, and a support system? Aside from size, you have to assess the quality of your interactions with the influencers that you surround yourself with and begin strategically seeking places where you can meet these persons. In many cases, your network will determine your future place of employment, among other things.
Working at larger places of employment has its benefits and drawbacks, too. At CDC, I understand how I fit as the cog in the machine. There is an obvious structure. As a larger organization, there is also an attractive benefits package that smaller organizations may not be able to offer.
Moreover, there are more opportunities to move internally if you become dissatisfied in your current department or simply want to gain another skill. Larger companies tend to offer a lot training and professional development programs, and may even offer to pay for advanced degrees.
Conversely, change moves at the speed of a turtle. There may be less camaraderie among coworkers, you might be relegated to doing the same thing repeatedly, and upward mobility may be stagnant as there are few supervisorial jobs compared to worker jobs. Persons employed at smaller companies may enjoy varied tasks, any achievement or failure does not go unnoticed, may get to know coworkers more familiarly, and the same problem of upward mobility may exist as senior managers are not readily leaving those positions.
Does Size Matter? Absolutely. Still, this is contingent upon understanding in what type of environments that you flourish best.