The postdoctoral fellowship period is designed to be a period of research training, as defined by the National Academies, “for the purpose of gaining scientific, technical, and other professional skills that advance the professional career”. The Graduate School of the University of Connecticut at Storrs defines a postdoctoral fellowship or a postdoctoral traineeship as a training experience for individuals with a Ph.D., Sc.D., M.D., D.V.M., or D.D.S. The primary focus of a postdoctoral fellowship or traineeship is research or scholarship. Faculty have a responsibility to mentor postdoctoral trainees and fellows. The Graduate School will have oversight responsibility.
By definition a training experience is temporary. Accordingly the duration of a postdoctoral fellowship or traineeship cannot exceed 5 years. These positions are distinct from non-tenure career positions such as Research Associates, Research Professors, and Professors-in-Residence.
Although both postdoctoral fellows and trainees are in training, those on training grants and fellowships are called trainees. Those on other sources of funds are called fellows. Individuals seeking another terminal degree concurrently cannot be a postdoctoral fellow or trainee.