**Abstract:**
Failure mode and effects analysis (FMEA) is a structured prospective risk assessment method that is widely used event logs. FMEA involves a multidisciplinary team mapping out a high-risk process of care, identifying the failures that can occur, and then characterizing each of these in terms of probability of occurrence, severity of effects and detect ability, to give a risk priority number used to identify failures most in need of attention. One might assume that such a widely used tool would have an established evidence base. This paper considers whether or not this is the case, examining the evidence for the reliability and validity of its outputs, the mathematical principles behind the calculation of a risk priority number, and variation in how it is used in practice. In this paper we described a model of FMEA and its failure and also explain various types of tools used in this method.

**Keywords:**
Single failure points (SFPS), Failure mode and effects analysis (FMEA).