Adam S. Chilton (Chicago) & Eric A. Posner (Chicago), An Empirical Study of Political Bias in Legal Scholarship, 44 J. Legal Stud. 277 (2015):
Law professors routinely accuse each other of making politically biased arguments in their scholarship. They have also helped produce a large empirical literature on judicial behavior that has found that judicial opinions sometimes reflect the ideological biases of the judges who join them. Yet no one has used statistical methods to test the parallel hypothesis that legal scholarship reflects the political biases of law professors. This paper provides the results of such a test. We find that, at a statistically significant level, law professors at elite law schools who make donations to Democratic political candidates write liberal scholarship, and law professors who make donations to Republican political candidates write conservative scholarship. These findings raise questions about standards of objectivity in legal scholarship.
Professors who are Democrats (adjusted)—shown in the left panel—have an average article ideology of -2.67 with a 90% confidence interval of -3.13 to -2.21. Using a t-test, we can say that this is statistically different from zero (p-value < 0.00). Professors who are Republicans (adjusted)—shown in the right panel—have an average article ideology of 0.17 with a 90% confidence interval of -0.72 to 1.10. For these professors, we cannot reject the possibility that the true net ideology of their articles is zero (p-value = 0.72). In other words, our data suggest that Democrats in our sample do not write articles that are on balance neutral, but that Republicans in our sample may write articles that are on balance neutral. ...
[I]f it is in fact the case that Republicans write less ideologically biased scholarship than Democrats do, then one would naturally ask why.
The most plausible explanation is that if the dominant ethos in the top law schools is liberal or left-wing,51 then Republicans are likely to conceal their ideological views in their writings. Republican professors might fear that scholarship that appears conservative may be rejected by leftleaning law review editors, and disparaged or ignored by their colleagues, which will damage their chances for promotions, research money, and lateral appointments. This would explain why even nondonors tilt left. Republicans could suppress their ideological views by avoiding controversial topics, taking refuge in fields that have little ideological valence, focusing on empirical or analytical work, or simply writing things that they don’t believe.
The data presented in Table 4 suggest that constitutional rights scholars are less ideologically diverse than other legal scholars. Among constitutional rights scholars, 77% are net Democratic donors, and 4% are net Republican donors. In the rest of the sample, 40% are net Democratic donors, and 20% are net Republican donors. It also shows that constitutional rights scholars are more likely to produce biased research (mean of -3.85 conservative articles) than Republican and Democratic scholars in other fields (mean of -1.35 conservative articles).