A method of monitoring and assessing program variables of an industrial installation driven by a controller (C) by instructions programmed in a user program. Specific monitoring modules (MS1 to MSt) are implanted, as close as possible in time to the variable(s) (V1 to Vt) to be monitored to monitor evolution in real-time. During execution, each specific monitoring module (MSy) reads, in real-time, the logic state of each of variables which it monitors in an instantaneous cycle turn (TCi) of the controller (C), compares this logic state with the previously recorded logic state, and, only in the case of a state change, records the new logic state read as well as the real-time time-stamp of this event in a global memory unit (UM_G). The recorded metadata is analyzed in order to check behavior of the installation, use this production data and identify a possible malfunction of program and/or the installation.