Editing Failure rate (section)

===Decreasing failure rates===

A decreasing failure rate describes cases where early-life failures are common<ref>{{Cite book | doi = 10.1007/978-1-84800-986-8_1 | chapter = Introduction | first = Maxim | last = Finkelstein| title = Failure Rate Modelling for Reliability and Risk | series = Springer Series in Reliability Engineering | pages = 1–84 | year = 2008 | isbn = 978-1-84800-985-1 }}</ref> and corresponds to the situation where <math>h(t)</math> is a [[decreasing function]].

This can describe, for example, the period of [[infant mortality]] in humans, or the early failure of a [[transistor]]s due to manufacturing defects.

Decreasing failure rates have been found in the lifetimes of spacecraft - Baker and Baker commenting that "those spacecraft that last, last on and on."<ref>{{Cite journal | last1 = Baker | first1 = J. C. | last2 = Baker | first2 = G. A. S. . | doi = 10.2514/3.28040 | title = Impact of the space environment on spacecraft lifetimes | journal = Journal of Spacecraft and Rockets | volume = 17 | issue = 5 | pages = 479 | year = 1980 | bibcode = 1980JSpRo..17..479B }}</ref><ref>{{Cite book | doi = 10.1002/9781119994077.ch1 | chapter = On Time, Reliability, and Spacecraft | first1 = Joseph Homer | last1 = Saleh | first2 =Jean-François | last2 =Castet| title = Spacecraft Reliability and Multi-State Failures | pages = 1 | year = 2011 | isbn = 9781119994077 }}</ref>

The hazard rate of aircraft air conditioning systems was found to have an exponentially decreasing distribution.<ref name="proschan">{{Cite journal | last1 = Proschan | first1 = F. | title = Theoretical Explanation of Observed Decreasing Failure Rate | doi = 10.1080/00401706.1963.10490105 | journal = Technometrics | volume = 5 | issue = 3 | pages = 375–383 | jstor = 1266340| year = 1963 }}</ref>