ABSTRACT
A crucial aspect of common-cause failures, which is not addressed in this paper, is their assessment, thoroughly investigated in (Mosleh et al. 1988; Mosleh 1991; Parry 1991) and many other references. If simple failure rate are not so easy to evaluate/measure, the situation is even worse for multiple-failure rates. This makes all propositions to derive such rates from scarce data all the more useful and crucial (Vaurio 2002). Various models (square-root, β, multiple Greek letters) have been discussed in (Fleming 1974; Spragins 1977; Vesely 1977; Atwood 1986; Mosleh et al. 1988; Dörre 1989; Qingxu andYouheng 1992; Levitin 2001; Rausand and Høyland 2004; Hokstad et al. 2006; Bérenguer et al. 2006; Dieulle et al. 2007), and many others.
