As a followup......This quote was made by Joernstu earlier in this thread.
Originally posted by joernstu
I cannot decide, what kind of action would induce the lowest risk - following an RA, not following an RA or flying without TCAS at all as the basis for my risk evaluation would be episodes. I think the same goes for you as your information basis is still only episodes
http://www.eurocontrol.int/msa/galle...n_9_Jul-07.pdf
I direct you to the Eurocontrol ACAS Bulletin #9 and quote...
"Five. The factor of collision risk reduction thanks to TCAS II in the operational world, taking into account some non TCAS II equipped aircraft, inaccurate pilot responses and lack of responses, altitude reporting inaccuracies, etc."
There have been some irresponsible statements made much earlier in this thread. It is rational to Follow The RA even if it contradicts an ATC instruction.