This study examined the problems of postgraduate research assistants in the Netherlands. The study was conducted as a result of Government plans to introduce a new educational system for obtraining a doctorate equivalent to a Ph.D.--the "assistants-in-training system" (aio system). On the basis of a literature study on the American and British Ph.D, a model was developed for assessing problems of Dutch research assistants (Ph.D students). As possible causes of these problems three categories were discerned: (1) background (age, gender, motives, etc.); (2) the discipline; and (3) the working environment (supervision, the department, etc.). A survey of research assistants (n=166) at six Dutch universities who were studying in the natural sciences, social sciences, and humanities revealed the following: that the influence of the discipline appeared to be substantial (background, working environment, and experienced problems); that the working environment also had a substantial effect on research assistant problems; and that research problems caused teaching problems. A new global causal model is presented for further research. Contains 14 references. (GLR)