Kyle Rozema (Washington University; Google Scholar), How Do Occupational Licensing Requirements Affect Labor Supply? Evidence from the Legal Profession:

I investigate the effect of occupational licensing on the size of the U.S. legal profession. To do so, I develop a new method for estimating the effect of occupational licensing requirements on labor supply in professions that have long been regulated and will likely continue to be regulated in some form. I report three primary findings. First, I find that the bar exam has a much larger impact on the size of the legal profession than the law degree requirement. Second, I find that differences between the most lenient and strictest bar exam policies would affect the size of the legal profession more than eliminating the bar exam. Finally, I find that small and often overlooked policies on the timing of licensing cumulatively have a non-trivial effect on the size of the legal profession. 

ABA Journal, How Could Alternative Licensure Alter Lawyer Labor Supply? Law Prof's Research May Have Answers:

If jurisdictions eliminate the bar exam as an entry to attorney licensure, the labor supply of lawyers would increase by 16%, according to new research by Kyle Rozema, an associate professor at the Washington University School of Law in St. Louis. …

Additionally, Rozema found that the labor supply of lawyers would increase by 8% if states adopt the most lenient bar exam policies and would decrease by 14% if the strictest policies are adopted.