Nearly every institution of higher education champions diversity. There are good reasons for this.  Diversity of viewpoints, perspectives and experiences can enrich educational environments and facilitate critical examination of complex issues. Yet some forms of diversity are clearly more important to academic institutions than others.

Arthur C. Brooks writes in the New York Times:

Scholarly studies have piled up showing that race and gender diversity in the workplace can increase creative thinking and improve performance. Meanwhile, excessive homogeneity can lead to stagnation and poor problem-solving.

Unfortunately, new research also shows that academia has itself stopped short in both the understanding and practice of true diversity — the diversity of ideas — and that the problem is taking a toll on the quality and accuracy of scholarly work.

The ideological imbalance that pervades academia fosters groupthink and undermines critical thinking. The dominance of left-leaning perspectives in academic institutions compromises their commitment to open inquiry and effective education.

Among other things, liberals and conservatives alike can fall prey to motivated reasoning and confirmation bias. One benefit of ideological and viewpoint diversity is that it can provide a check on such tendencies. Writes Brooks:

But even honest researchers are affected by the unconscious bias that creeps in when everyone thinks the same way. Certain results — especially when they reinforce commonly held ideas — tend to receive a lower standard of scrutiny. This might help explain why, when the Open Science Collaboration’s Reproducibility Project recently sought to retest 100 social science studies, the group was unable to confirm the original findings more than half the time. . . .

Brooks cites a recent paper from the journal Behavioral and Brain Sciences documenting the causes and effects of the lack of ideological diversity in social psychology. While a large number of factors contribute to ideological imbalance, the authors cite evidence that conscious bias is among them.

The lack of ideological diversity is a particular problem for law schools as it leaves many law students unexposed to perspectives and arguments with which they will have to contend in the practice of law. Most legal academics are well to the left of those whom law students will represent, as well as to the majority of judges before which they will practice. One need not agree with one’s client or a judge to be an effective advocate, but it is important to understand the perspective of the position one has to represent — as well as the perspective of the other side. The best legal advocates fully comprehend the strongest arguments for the other side and are able to present arguments that can appeal to decision-makers who may approach difficult legal questions from a perspective quite different from their own. On many issues, however, the perspectives of legal academics are relatively monolithic and reflect little understanding of (let alone sympathy for) common right-of-center viewpoints.

Brooks concludes:

Improving ideological diversity is not a fundamentally political undertaking. Rather, it is a question of humility. Proper scholarship is based on the simple virtues of tolerance, openness and modesty. Having people around who think differently thus improves not only science, but also character.

This is true, but there is relatively little evidence that most institutions of higher education much care, and even less that they are doing anything about it.

UPDATE: Here is a follow-up post on the causes of ideological imbalance in the academy.