The performance assessment of industrial operators is a challenge faced by the scientific community in last decades on account of the subjectivity involved, lack of quantitative methods and complex trainer-trainee- relation. This paper presents a methodology to evaluate the performance of a control room operator according to operator performance indicators based on relevant human factors, which allows a quantitative and as well as qualitative assessment. The proposed methodology can be used not only for the assessment of operators but also for scheduling training courses, future recruitments, and insurance evaluations.