Editing Fault tree analysis (section)

==Comparison with other analytical methods==
FTA is a [[Deductive reasoning|deductive]], top-down method aimed at analyzing the effects of initiating faults and events on a complex system. This contrasts with [[failure mode and effects analysis]] (FMEA), which is an [[Inductive reasoning|inductive]], bottom-up analysis method aimed at analyzing the effects of single component or function failures on equipment or subsystems. FTA is very good at showing how resistant a system is to single or multiple initiating faults. It is not good at finding all possible initiating faults. FMEA is good at exhaustively cataloging initiating faults, and identifying their local effects. It is not good at examining multiple failures or their effects at a system level. FTA considers external events, FMEA does not.<ref>{{Citation
 |last        = Long
 |first       = Allen
 |title       = Beauty & the Beast &ndash; Use and Abuse of Fault Tree as a Tool
 |url         = http://www.fault-tree.net/papers/long-beauty-and-beast.pdf
 |publisher   = fault-tree.net
 |access-date  = 16 January 2010
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20090419200036/http://www.fault-tree.net/papers/long-beauty-and-beast.pdf
 |archive-date = 19 April 2009
}}
</ref> In civil aerospace the usual practice is to perform both FTA and FMEA, with a [[Failure mode and effects analysis|failure mode effects summary]] (FMES) as the interface between FMEA and FTA.

Alternatives to FTA include [[Reliability block diagram|dependence diagram]] (DD), also known as [[reliability block diagram]] (RBD) and [[Markov analysis]]. A dependence diagram is equivalent to a success tree analysis (STA), the logical inverse of an FTA, and depicts the system using paths instead of gates. DD and STA produce probability of success (i.e., avoiding a top event) rather than probability of a top event.