What is the Actual Number of Active US Clinical Trial Investigators?


Applied Clinical Trials

Estimates of active US investigators range from about 20,000 to almost 150,000.

Understanding the investigator landscape is essential for drug development professionals. This may range from questions about broad trends to more operational issues such as finding the most appropriate clinical investigators for a specific clinical trial. Data from ClinicalTrial.gov indicate that the United States remains the center of global clinical trial activity, by far the most active of any country. The US clinical investigator arena then remains a critical element in global clinical trial activity. 

Claims about the number of US clinical trial investigators active in the conduct of industry-sponsored studies are usually based more on subjective judgment than verifiable data. Estimates of active US investigators range from about 20,000 to almost 150,000. 

The US government, through the Sunshine Act, requires that all payments to physicians by the pharmaceutical and medical instruments industries be reported in the Open Payments database. The reported details allow us to establish the actual number of active, unique, US clinical trial investigators. Over the last two complete years reported in the database, 2015-2016, 39,855 principal and sub-principal investigators took part in industry-sponsored clinical trials. No doubt some investigator may have started clinical trials for the first time in 2017, just as a number of the investigators, active in the two reported years, may have discontinued their clinical trial participation. 

It is even possible to identify the number of active investigators in any given year by medical specialty. The chart below reports the ten most frequently mentioned specialties. Most investigators appear in both years.   


Number of Active Clinical Trial Investigators Each Year

By The 10 Most Frequently Reported Medical Specialty