The vibrant national debate over the extent of liberal bias on campus has been raging for several decades. Many critics on the right depict higher education as a “liberal echo chamber” (p. 120) that has fostered such evils as the repression of academic freedom, the brainwashing of students, and discriminatory conduct. Many critics on the left counter that conservatives seriously exaggerate the problem for their own political reasons.

Few scholars have addressed fundamental questions in this culture war with the tools of empirical social science. Enter Neil Gross with Why Are Professors Liberal and Why Do Conservatives Care? The book is the product of “seven years of intensive social scientific research” (p. 5), much of which Gross and his collaborators have previously presented in leading social science journals.

Why Are Professors Liberal? may leave some key questions dangling, but that being said, it is a sort of tour de force of social scientific inquiry. Even skeptics must acknowledge the breadth and fairness of Gross’s research and his efforts to honor the Weberian researcher’s obligation to keep one’s facts separate from one’s values. (Gross confesses to being a political liberal, but he succeeds in holding his politics in abeyance.) Gross also scrupulously recognizes the provisional nature of many of his conclusions. Another sign of the book’s integrity is that its conclusions will no doubt unsettle both sides of the partisan divide.

Though Gross carefully dissects many social science theories, his book boils down to the pursuit of four questions: Is the professoriate decidedly liberal-left in its composition? If so, why is this the case? Why do conservatives care? (I would further ask why we, the people, should care. See below.) And what impact does any discernible liberal bias have on how professors teach, construe their professional obligations, and behave toward their colleagues?

Regarding the second question, Gross proposes in Chapters 6 and 7 that conservatives have targeted academia as a convenient way to discredit liberalism in general. This thesis is interesting, provocative, and plausible in respect to at least some activists, but this section of the book seems more speculative in terms of evidence than the parts devoted to the other questions.

To answer the other questions, Gross conducts several empirical inquiries, including a survey of the general public’s perceptions of liberal bias in academia; a random survey of the political and social views of 1400 academics; free-form interviews with 57 professors who teach in five different disciplines; analysis of the General Social Survey (GSS), which has surveyed large numbers of academics and non-academics since 1970; examination of a leading longitudinal study of adolescents who went on to graduate school for a Ph.D.; and an email “audit survey” of directors of graduate programs in five disciplines. Gross then complements this veritable empirical armada by considering how well the data fit leading social science theories that attempt to explain the politics of academia.

Like previous researchers, Gross finds academia to be decidedly liberal-left, especially compared to the general public, which is center-right. Indeed, academia is more liberal than any other occupational group, with the possible exception of authors and journalists. But professors, as a group, are not monolithic. Moving left to right across the different types of academic institutions, one finds: 9% “radical left;” 31% “progressive;” 14% “center-left;” 19% “moderate;” 4% “economic conservative;” and 23% “strong conservative.” Not surprisingly, the proportions differ depending upon the type of institution and discipline. For example, liberal arts schools are more radical, while community colleges and non-Ph.D. granting universities are more moderate. Humanities and the social sciences tilt decidedly left, with the exception of economics. Engineering and business are more conservative and moderate.

The key question for Gross is why academia leans so left. Is this situation due to invidious intent or more sanguine causes? Using the GSS as a compass, Gross finds the leading conventional explanations for liberal tilt to be implausible or only partially valid. Such explanations vary in their quality, from Bordieu’s class-position theory of academic politics (sophisticated) to leftists who claim that conservatives are more materialistic or just not typically smart enough to hack it as academics (unsophisticated). Other intriguing theories also fall short of the prize. When all the smoke clears, the main reason there are more lefties than righties in academia is “self-selection.”

The longitudinal study indicates that the “single most important statistical factor” accounting for the political gap between professors and society is who decides to go to graduate school (p. 105). What influences this decision? “Historical contingency” in the modern university’s early twentieth-century development led to academia being politically “typed” as liberal-progressive (p. 140). “Political typing” is similar to “sex typing,” in which certain jobs become associated with a specific gender. In both cases, typing reflects an original more or less objective reality while also causally exacerbating it. There is no conspiracy, just the circumstantial confluence of political issues, key personalities, and the endogenous forces that shape intellectual trends and fashion. Gross’s discussion in Chapter 5 of the internal dynamics that influence the developmental content of disciplines is very instructive regarding this endogeneity. Academia’s deserved liberal reputation is congruent with liberals’ “self-congruence concept,” but incongruent with conservatives’ sense of self. Consequently, “few conservative students are likely to feel completely at home and comfortable in the contemporary American academic environment” (p. 108). Typing influences young people even before they enter college. In one major survey, 50% of the freshmen who aspired to be academics were liberal, whereas only 20% were conservative.

The prevalence of self-selection (Gross does not claim it is the only explanation) generally acquits academia of the charge of systematic invidious bias. Furthermore, most—though not all—of the left-oriented academics in Gross’s samples eschew discrimination and politicization because they consider political orientation irrelevant to their fields and/or because of their sense of professional obligation. Gross’s email audit study of graduate student directors in major departments provides some support for this assessment (pp. 163-67). This assessment is more or less consistent with my own thirty-year experience at a major research university that has long been indelibly “typed” as a left-liberal institution. Conservative critics of higher education should take heed.

That said, not all is well in the state of Denmark. Gross’s own evidence shows that “some conservative graduate students and professors face hostility and inhabit politically uncomfortable educational and occupational worlds,” especially in certain disciplines (p. 162). And Gross’s data, including the audit survey, does not really get at the more subtle forms of unequal treatment that “in-group” mentality can engender or encourage. Consider this question: Would it not be a form of professional malpractice for an advisor to not warn a conservative prospective graduate student in the social sciences or humanities of climate problems and bias he or she might encounter? Given Gross’s findings, exaggerating this possibility would also be irresponsible.

Two important concerns lie outside the scope of Gross’s focus. First, Gross does not deal with the administrative class in academia—the so-called “shadow university,” which is academia’s version of the “deep state.” But it is often this ineluctably growing class—tacitly supported by faculty who look the other way or are too busy to bother—who impose or enforce speech codes and other chilling policies that reinforce reigning campus orthodoxies, which are likely to be liberal-left according to Gross’s findings. Second, what is the effect on the education experience? This is something that we, the people, should care about. Would education be more probing, truthful, and beneficial to society—and more exciting—if a more balanced diversity of political viewpoints existed on campus? The likes of John Stuart Mill and Alexander Meiklejohn certainly would have thought so.