List of research universities in the United States
This is a list of universities in the United States classified as research universities in the Carnegie Classification of Institutions of Higher Education. Research institutions are a subset of doctoral degree-granting institutions and conduct research. These institutions "conferred at least 20 research/scholarship doctorates in 2019-20 and reported at least $5 million in total research expenditures in FY20 were assigned to one of two categories based on a measure of research activity." History. The 1994 edition of the Carnegie Classification defined Research I universities as those that: The Carnegie  Foundation reported that 59 institutions met these criteria in 1994. In their interim 2000 edition of the classification, the Carnegie Foundation renamed the category to "Doctoral/research universities-extensive" in order to avoid the inference that the categories signify quality differences." The foundation replaced their single classification system with a multiple classification system in their 2005 comprehensive overhaul of the classification framework so that the term "Research I university" was no longer valid, though many universities continued to use it. In 2015, the Carnegie Classification System reinstated the "Research I university" designations along with "Research II" and "Research III." The  current system, introduced in 2018, includes the following three categories for doctoral universities: In the 2018 classification, institutions were classified as either R1 or R2 if they "conferred at least 20 research/scholarship doctorates in 2016-17 and reported at least $5 million in total research expenditures." A "research activity index" was then calculated that included the following measures: These four measures were combined using principal component analysis to create two indices of research activity, one representing an aggregate level of research activity and the other representing per-capita research activity. Institutions that were high on both indices were  classified among "R1: Doctoral Universities – Very high research activity." Universities classified as "R1: Doctoral Universities – Very high research activity". There are 146 institutions that are classified as "R1: Doctoral Universities – Very high research activity" in the Carnegie Classification of Institutions of Higher Education as of the 2021 update. These universities have a very high level of both research activity and per capita in such research activity, using aggregate data to determine both measurements. In other words, these institutions provide a lot of resources for research and have a lot of people conducting research at their respective institution. These two classifications  can be seen as the aggregate supply and aggregate demand of research, respectively. Universities classified as "R2: Doctoral Universities – High research activity". There are 133 institutions that are classified as "R2: Doctoral Universities – High research activity" in the Carnegie Classification of Institutions of Higher Education as of the 2021 update. These universities have a very high level of either research activity or per capita in such research activity, using aggregate data to determine both measurements, while having a very low level on the other qualification. In other words, these institutions either lack research facilities or do not have a lot  of people conducting research at their respective institution. These two classifications can be seen as the aggregate supply and aggregate demand of research, respectively. Universities classified as "Special Focus - Research Institutions". There are 23 institutions that are classified as "Special Focus - Research Institutions" in the Carnegie Classification of Institutions of Higher Education as of the 2021 update. This new category has the same threshold for inclusion as R1 and R2 schools do (At least twenty research doctorates awarded and five million dollars in research expenditures), but unlike R1 and R2 schools, they only award degrees in a single academic area