The paper proposes a generalized methodology for evaluation the performance indicators of the ergatiс information system, which is based on an algorithmic model of the operator's activity and takes into account its reliability. For this purpose, the process of operator activity is represented in the form probabilistic graph, which is a graphical representation of individual operations and allows to describe the algorithm mathematically, to evaluate its hourly and probabilistic indicators using the rules of transformation graph-scheme. Proceeding from the purpose of the ergatiс information system, the tasks that it solves, the indicators are selected the effectiveness of its operation. The order of their calculation is given. The influence exerted by the operator reliability on the efficiency performance of the ergatiс information system is taken into account by means a coefficient which characterizes the operator's ability to work. By the example radio-monitoring system calculations indicators efficiency of its functioning are carried out.