Why advisers have to get under the skin of modelling tools

Wouldn't it be great if markets performed in exactly the way they had done in the past? If, every year equities managed to generate the 5% real return they have averaged since 1899 then advising on income drawdown would be a piece of cake? But as we all know, markets don't work in straight lines, even though a surprising number of projection tools, offered by big-name organisations, behave as though they do. Advisers are putting themselves and their clients at very serious risk if they do not understand the considerable difference in the accuracy of the best and the worst financial...