The higher-raking US universities are private because of their donors, history and prestige. Private universities are typically smaller in size with only a few hundred to thousand students compared to public universities, therefore they are able to specialize or cater to a more specific demographic. The cost of tuition is higher thereby attracting higher educated teachers. The class sizes are smaller ensuring more one-on-one time between the teacher and student. The environment of the campus is typically smaller, more intimate in nature and allows for deeper connection among the faculty and students. Private universities also have more freedom over their curiculum and class schedules allowing for a more creative and intellectual culture.

Investment into research is one of the factors that keeps high-ranking private universities at the top of the lists of US university rankings. This is made possible by the funds that these universities have and continue to receive from their alumni. The Endowment Fund that most private Universities possess runs into the hundreds of Millions of Dollars. And Grants from governments also are received for research which makes these institutions unfettered by any financial stress.

In contrast, Public Universities are receiving consistently lesser funding over the last three decades. This then leads to reputed faculty moving to private Universities where they can continue with their research without any worry about budgetary allocations. With a higher investment into research, cited researchers and published papers which are a component of University rankings, are also quite higher amongst private Universities.

The student-teacher ratio is also quite lower at private universities than at public universities which take in students in the tens of thousands. As intake into private Universities is very competitive, the rate of graduation is better at private Universities.