Ford Foundation
In 1955, Robert Maynard Hutchins led an effort within the Ford Foundation to document and analyze the effects of McCarthyism on academic freedom. He commissioned sociologist Paul Lazarsfeld to conduct a study of university faculty in the United States, and the results were published by Lazarsfeld and Wagner Thielens in a book, The Academic Mind. As part of a survey of faculty views about academic freedom during the "Second Red Scare", they asked 2,451 professors of social science a large number of questions, and found that about two thirds of these faculty members had been visited by the FBI and had been asked questions about the political beliefs of their colleagues, students, and themselves. They also included a few questions about political party affiliations and recent voting patterns, and reported that there were more Democrats than Republicans, 47% to 16%. According to sociologist Neil Gross, the study was significant because it was the first effort to poll university faculty specifically about their political views.
Carnegie Commission on Higher Education
The Lazarsfeld and Thielens study had examined a sample of 2,451 social science faculty members. A second study, conducted in 1969 on behalf of the Carnegie Commission on Higher Education, was the first to be performed with a large survey sample, extensive questions about political views, and what Neil Gross characterized as highly rigorous analytic methods. The study was conducted in 1969 by political scientist Everett Carll Ladd and sociologist Seymour Martin Lipset, who surveyed 60,000 academics in multiple fields of study at 303 institutions about their political views. Publishing their results in the 1975 book The Divided Academy, Ladd and Lipset found that about 46% of professors described themselves as liberal, 27% described themselves as moderates, and 28% described themselves as conservative. They also reported that faculty in the humanities and social sciences tended to be the most liberal, while those in "applied professional schools such as nursing and home economics" and in agriculture were the most conservative. Younger faculty tended to be more liberal than older faculty, and faculty across the political spectrum tended to disapprove of the student activism of the 1960s.
Smaller follow-up surveys on behalf of the Carnegie Foundation held in 1975, 1984, 1989, and 1997 showed an increased trend among professors toward the left, apart from a small movement to the right in 1984. By the 1997 study, 57% of the professors surveyed identified as liberals, 20% as moderates, and 24% as conservatives.
Later surveys
As later surveys were published, some scholars pointed to the harmful effects of a political imbalance in the faculty, and one editorial described the effects as "ruining college". Other scholars said that there were serious methodological problems that led to overestimates of the disparity between liberals and conservatives, and that there were political motivations for such overestimates.
Higher Education Research Institute
Beginning in 1989, the Higher Education Research Institute (HERI) at the University of California, Los Angeles has conducted a survey of full-time faculty at American four-year colleges and universities every three years. The HERI Faculty Survey gathers comprehensive information about the faculty experience, such as position, field, institutional details, and personal opinion and views, including a single question asking respondents to self-identify their political orientation as "far left", "liberal", "moderate/middle of the road", "conservative", or "far right". Between 1989 and 1998, the survey showed negligible change in the number of professors who described themselves as far left or liberal, approximately 45%. As of 2014, surveying 16,112 professors, the percentage of liberal/far left had increased to 60%. When asked in 2012 about the significance of the findings on political views, the director of HERI, Sylvia Hurtado, said that the numbers on political views attract a lot of attention, but that this attention may be misplaced because there may be trivial reasons for the shifts.
North American Academic Survey Study
Ladd and Lipset, who had conducted the original Carnegie survey, designed a telephone survey in 1999 of approximately 4000 faculty, administrators, and students, called the North American Academic Survey Study (NASS). Stanley Rothman, the project lead after the passing of Ladd and Lipset, published a paper using NAASS data along with Neil Nevitte and S. Robert Lichter which concluded "complaints of ideologically-based discrimination in academic advancement deserve serious consideration and further study". Rothman along with co-authors Matthew Woessner and April Kelly-Woessner reported their extended findings in a book titled The Still Divided Academy.
Politics of the American Professoriate
Neil Gross and Solon Simmons conducted a survey starting in 2006 called the Politics of the American Professoriate which led to several study papers and books. They designed their survey to improve on past studies which they felt had not included community college professors, addressed low response rates, or used standardized questions. The survey drew upon a sample size of 1417 full-time professors from 927 institutions.
In 2007, Gross and Simmons concluded in The Social and Political Views of American Professors that the professors were 44% liberal, 46% moderates, and 9% conservative. Inside Higher Ed reported that economist Lawrence H. Summers made his own analysis of the data collected by Gross and Simmons and found a larger gap among faculty teaching "core disciplines for undergraduate education" at selective research universities, but the report also concluded that "there was widespread praise for the way the survey was conducted, with Summers and others predicting that their data may become the definitive source for understanding professors' political views."
Gross published a more extensive analysis in his 2013 book Why Are Professors Liberal and Why Do Conservatives Care? and, with Simmons, in their 2014 compilation Professors and Their Politics. They strongly criticized what they saw as conservative political influence on the interpretation of data about faculty political views, arising from activists and think tanks seeking political reform of American higher education. Sociologist Joseph Hermanowicz described Professors and Their Politics as "a welcome addition to sociological literature examining higher education, which, in the case of its intersection with politics, has not received serious attention since Paul Lazarsfeld and Wagner Theilen's classic study of 1958 and Seymour Martin Lipset and Everett Carll Ladd's 1976 work."
Regional and disciplinary variations
Several studies have found that the political views of academics vary considerably between different regions of the United States, and between academic disciplines. In a 2016 opinion column in The New York Times, for example, political scientist Samuel J. Abrams used HERI data to argue that the ratio of liberal to conservative faculty varied greatly between regions. According to Abrams, the ratio of liberal to conservative professors was highest in New England, where this ratio was 28:1, compared to 6:1 nationally. Abrams also commented on these findings that "This previously unspecified ideological imbalance on campuses has led to cries of discrimination against right of center professors and scores of reports from both academic and popular press sources which have chronicled the concerns with this "beleaguered" and "oppressed" minority on campus... The data clearly reveal that conservative faculty are not only as satisfied with their career choice - if not more so - as their liberal counterparts, but that these faculty are also as progressive in their teaching methods and maintain almost identical outlooks toward their personal and professional lives."
Mitchell Langbert examined variations in political party registration in 2018, describing a higher concentration of Democrats in elite liberal arts institutions in the northeast, and found more Democrats among female faculty than male faculty. He also found the greatest ratio of Democrats to Republicans in interdisciplinary studies and the humanities, and the lowest ratio in professional studies and science and engineering.
Focusing specifically on social psychology academics, a 2014 study found that "by 2006, however, the ratio of Democrats to Republicans had climbed to more than 11:1." The six authors, all from different universities and members of the Heterodox Academy, also said, by 2012, "that for every politically conservative social psychologist in academia there are about 14 liberal psychologists" according to Arthur C. Brooks. Academy member Steven Pinker described the study as "one of the most important papers in the recent history of the social sciences". Russell Jacoby questioned the focus of the study on the social sciences rather than STEM fields saying that the "reason is obvious: Liberals do not outnumber conservatives in many of those disciplines".