International audience— Diagnosability is the ability to detect a fault from partial observations collected on a system. It has been studied for numerous models of discrete event systems, but essentially from a logical perspective. This paper explores quantitative versions of the problem, to evaluate " how much " a system is (non-)diagnosable. For the diagnosable part of a system, that we characterize, we then examine the probability distribution of the detection delay. We show that the mean and the standard deviation of the detection delay can be easily evaluated
