The United States system of higher education is not so much a formal system as an informal configuration of different institutions. The development of the American system has been unique compared to other national systems of higher education around the world. Unlike most other countries, where higher education systems have largely evolved from a central, state-supported university, the United States has never had such an institution. Rather, the evolution of the U.S. system has been shaped by many different factors, including state and local needs, demographics, religion, and changing social contexts. As a result, institutions of higher education in the United States reflect the multifaceted complexity of the broader society in which they are embedded and the diversity of the people they serve. Moreover, American higher education is highly disordered in structure and operation, unlike many national postsecondary education systems, and even in stark contrast to the rationally organized American system of compulsory elementary and secondary education.

Higher education institutions and the students they serve are diverse and not easily categorized. This disorder is characterized by a diversity of individual institutional goals and missions, types of degrees offered, financial and management structures, and even curricula, course content, and teaching methodologies. Institutions of higher education and the students they serve are diverse and not easily categorized. This disorder is characterized by a diversity of individual institutional goals and missions, types of degrees offered, financial and management structures, and even curricula, course content, and teaching methodologies. Institutions of higher education and the students they serve are diverse and not easily categorized. This disorder is characterized by a diversity of individual institutional goals and missions, types of degrees offered, financial and management structures, and even curricula, course content, and learning methodologies.

To understand how this informal and vaguely structured “system” of diverse institutions serves the wide range of needs of American society, it is necessary to identify some of the main features that define the main types of institutions found in American higher education. In 1983, Robert Birnbaum noted that institutional diversity can be defined by several categories of institutional characteristics. The most useful of these categories include defining differences in terms of the following aspects of institutional diversity: systemic, structural, constitutive, and reputational.