The paper discusses the specifications and features of an automated assessment procedure for training of industrial operators. A case study applied to a real catalyst‑injector‑switch procedure in a polymer plant is presented and commented. The automated assessment procedure is made possible by the Plant Simulator tool that is conceived to log the actions of the operators, who are trained in its 3D immersive virtual environment, and the values of the process variables, which are simulated by a dynamic process simulator that runs in the background. The automated assessment procedure helps the trainer focusing on more human-oriented issues and leaves the quantitative marks/scores to the computer algorithm that analyzes and processes the trainee’s actions. The performance assessment is then characterized by an aseptic judgment that can be invoked as many times as one pleases. Actually, the automated performance assessment is unbiased and does not make distinctions of age, sex, race, experience. During the training session (that is propaedeutic to the assessment one), the performance assessment can be run also by the trainee alone without the psychological pressure exerted by the presence of the trainer/examiner. In addition, being systematic and automated, the performance assessment can be of real help for both trainers and decision makers. Trainers and managers can use the quantitative evaluation of performance assessment for decision-making purposes. The automated procedure allows also scheduling operators’ shifts in case of complex or periodic procedures, planning training courses, recruiting, and taking insurance related decisions.