Dougherty's dilemma and the one-sidedness of human reliability analysis (HRA)

Abstract Broadly speaking I agree with Dougherty's conclusions in his analysis of the current state of HRA, although there are some points which suggest rather different lines of thought. My conclusion is, however, that things are actually worse than he thinks, and can not even in principle be made better except to warn people that our predictions are one sided: any estimate is a number which states that you can expect the probability of error to be at least as great as that number, and usually more so, but never less. Furthermore, you will never know from moment to moment how much worse things are.