The purpose of the study was to investigate the relationship between the extent to which an actual vocational setting is simulated in teaching and the competency of students in performing radiographic technique. The research design randomly placed the students, after a lecture on gall bladder technique, into one of three simulation treatments, varying in degree of sophistication. The students were evaluated on patient-care ability, technical ability, and organizational ability. These evaluations were conducted before the simulation, after the simulation, and 10 days later to test retention. The results indicated a significant difference between the technical and organizational ability scores of students subjected to the three different simulations. However, no significant difference was indicated among the patient-care ability scores. It was concluded that technical and organizational abilities of students are enhanced by more realistic simulation treatments, while patient-care abilities are not affected by varying degrees of simulation. Students retain for a 10-day period what they practice in simulation, but no simulation treatment is more effective in retention than any other. (JR)