My point was to take as given all those other issues and assume that the decision threshold was established. This is quite a pragmatic issue. Many family cancer clinics offer prophylactic surgery at a given risk threshold. If the odds ratio estimate for a given gene were 3 (0.3 - 30) then it is unlikely that anyone would be testing for that gene at all. The idea that clinicians would be carrying out some complex sliding scale decision analysis seems unlikely. So, at what level of precision does it become useful to do testing for that gene?