Why FRACAS is important for medical device manufacturers

I have commented before that FMEA (and FTA) are used to prevent potential errors and that FRACAS is used to prevent the recurrence of observed errors. FRACAS is easier than FMEA, FTA because for FRACAS:

·         no modeling is required with respect to enumerating the possible failure modes (errors) – one simply observes the errors

·         one can easily calculate a failure rate, which can also help  predict when a failure rate goal will be achieved

From a user’s perspective (e.g., medical device customer), it is of course more important to prevent errors than to prevent their recurrence (e.g., no melt down vs. preventing another melt down). However, if FRACAS is completed before release for sale, then the FRACAS activity of preventing the recurrence of observed errors is also preventing potential errors from the user’s perspective, because (again, from the user’s perspective) the clock is at zero – no errors have occurred yet because the system hasn’t been used. This is summarized in the following table.

Tool Before release for sale After release for sale
  Errors are: Control measures used to Effect of tool:


Prevent potential errors

Errors prevented



Prevent recurrence of errors

Errors prevented

This does not mean that FMEA, FTA should be dropped. If a potential error has never been observed, one still must be sure that adequate control measures are in place.

So FRACAS is part of risk management in spite of the fact that it is not mentioned in ISO 14971.


FMEA – Failure mode Effects Analysis
FTA – Fault Tree Analysis
FRACAS – Failure Reporting And Corrective Action System
Failure Mode – Error

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