On the heels of Matt Leichter’s recent work on law school faculty sizes, I looked at some of the data myself. I limited myself to 2011 to the present, because that’s the only data disclosed by the ABA in a usable format. (Older 509 data is available but is bound in isolated PDFs until some good soul helps liberate it.)
Adding to the complexity are methodological changes by the ABA. It used to separate “full-time” tenured and tenure-track faculty from “other full-time” faculty, such as clinicians. In 2014, it did not separate those categories, but it also yielded a fairly significant one-year decline in that category, suggesting confusion or misreporting of data. And further adding to the complexity are seemingly-random fluctuations in faculty sizes from year to year, or stark differences between fall and spring terms, likely because the data is not serious accounted for and leaves errors.