a 25 sigma loss was truly unlucky and points out that ``the probability of a 25 sigma event is comparable to the probability of winning the lottery 21 or 22 times in a row''. After financial crises or large trading losses, people responsible for monitoring risk often claim that the losses were 'unpredictable' or 'unprecedented' even though it seems much more likely that incorrect models were to blame.

a) How would you incorporate this idea into your risk management practice?