Here’s a link to the full report by Daniel Klein and Christopher Cardiff on faculty affiliations.
“The party registration of tenure-track faculty at 11 California universities, ranging from small, private, religiously affiliated institutions to large, public, elite schools, shows that the “one-party campus” conjecture does not extend to all institutions or all departments. At one end of the scale, U.C. Berkeley has an adjusted Democrat:Republican ratio of almost 9:1, while Pepperdine University has a ratio of nearly 1:1. Academic field also makes a tremendous difference, with the humanities averaging a 10:1 D:R ratio and business schools averaging 1.3:1, and with departments ranging from sociology (44:1) to management (1.5:1). Across all departments and institutions, the D:R ratio is 5:1, while in the “soft” liberal-arts fields, the ratio is higher than 8:1. These findings are generally in line with comparable previous studies.”