The first-ever OLLRP tracks key occupational licenses in all 50 U.S. states from the 1990s to today, with more professions and historical years to come
Morgantown, WV — Today, the Knee Regulatory Research Center—a nonpartisan research center focused on labor, health, and regulatory frontiers—announced the release of the Occupational Licensing Law Research Project Database (OLLRP), the first installment of a data project that tracks historical annual requirements to obtain licenses for key occupations in every U.S. state from 1991 to today. The first installment of the longitudinal, historical project starts with 10 universally or partially licensed occupations, including cosmetologists, physicians, and registered nurses, with more licensure data set for release in the months ahead.
Sponsored by the Knee Center, the National Bureau of Economic Research, the Federal Reserve Bank of Minneapolis, and other partners, the OLLRP can be accessed here.
The OLLRP is a first-of-its-kind database that unpacks the regulatory landscape of occupational licensing in unprecedented depth and detail for various audiences—from economists to employers and employees. Built with the help of economists, lawyers, and the Knee Center’s experienced team of researchers, the database identifies the specific state statutes, codes, and regulations related to occupations of note. It compiles research that dates back years before it was tracked by other experts and databases dedicated to occupational licensure. The following occupations are now available (with more professions and historical years to come):
- Optometrist (universally licensed)
- Physician Assistant (universally licensed)
- Physician (universally licensed)
- Registered Nurse (universally licensed)
- Cosmetologists (partially licensed)
- Dispensing Opticians (partially licensed)
- Licensed Practical Nurse (partially licensed)
- Massage Therapist (partially licensed)
- Professional Counselor (partially licensed)
- Respiratory Therapist (partially licensed)
The release of the OLLRP comes at a time when occupational licensing is especially pertinent to tens of millions of working Americans. As of 2025, 21.6 percent of U.S. jobs require an occupational license. Overly burdensome licensure keeps qualified people out of the labor market and drives businesses to other states, in the name of quality and safety. And yet, economists have repeatedly found that higher fees and arbitrary additional education or experience requirements do not affect consumer safety or satisfaction.
“Our team at the Knee Regulatory Research Center couldn’t be more excited about the release of the Occupational Licensing Law Research Project Database,” said Dr. Conor Norris, Director of Labor at the Knee Center. “This project has been a massive undertaking, but it will be a fantastic addition to the data available to researchers, helping people in our field and members of the general public answer questions that were once thought unanswerable. One of our top goals at the Knee Center is to help policymakers design the best possible policies when it comes to occupational licensing, and the OLLRP is a pivotal next step in achieving that goal.”