According to a recent study by the Tufts Center for the Study of Drug Development, global clinical trial performance and efficiency are hampered by high turnover and noncompliance among principal investigators and wide variation in investigative site experience.   While the number of investigators globally now stands at nearly 40,000, half of which were new in 2013, according to Tufts CSDD. Also, the highest turnover rates were observed among the least active investigators, and turnover rates ha...