It is quite common to compare FMEAs and fault trees because these two reliability analysis methods collect similar types of data. However, these methods are generally quite different in scope. A FMEA is usually broad in scope. A fault tree is usually targeted in scope, making it much faster to perform. For example, a fault tree is most effective when the undesired event or top event to analyze is clearly defined.

FMEA terms such as failure mode and end effect can be equated to fault tree terms such as basic event and top event. Taking a given FMEA end effect, a fault tree may be created. The end effect from the FMEA becomes the top event in the tree. Similarly, failure modes from the FMEA become basic events in the tree.

One limitation of FMEAs is that all failures are assumed to be mutually exclusive and not dependent on each other. This is in contrast to fault trees, where events that are joined using AND gates must all occur to cause the top event to occur. Both the FMEA and FTA modules provide a command for building a fault tree from the final results of a FMEA. For more information, see Building a Fault Tree from a FMEA.