on all previous observations Forecast errors can be evaluated using a variety of methods namely mean percentage error, root mean squared error, mean absolute percentage error, mean squared error. Other methods include tracking signal and forecast bias. For forecast errors on training data denotes the observation and is the forecast For forecast errors on test data denotes the actual value of the h-step observation and the forecast is denoted as Academic literature Dreman and Berry in 1995 "Financial Analysts Journal", argued that securities analysts' forecasts are too optimistic, and that the investment community relies too heavily on their forecasts. However, this was countered by Lawrence D. Brown in 1996 and then again in 1997 who argued that the analysts are generally more accurate than those of "naive or sophisticated time-series models" nor have the errors been increasing over time. Hiromichi Tamura in 2002 argued that herd-to-consensus analysts not only submit their earnings estimates that end up being close to the consensus but that their personalities strongly affect these estimates. Examples of forecasting errors Michael Fish - A few hours before the Great Storm of 1987 broke, on 15 October 1987, he said during a forecast: "Earlier on today, apparently, a woman rang the BBC and said she heard there was a hurricane on the way. Well, if you're watching, don't worry, there isn't!". The storm was the worst to hit South East England for three centuries, causing record damage and killing 19 people. Great Recession - The financial and economic crisis that erupted in 2007—arguably the worst since the Great Depression of the 1930s—was not foreseen by most forecasters, though a number of analysts had been predicting it for some time (for example, Stephen Roach, Meredith Whitney, Gary Shilling, Marc Faber, Nouriel Roubini, Brooksley Born, and Robert Shiller). The failure of most forecasters to forecast the "Great Recession" caused soul searching in the profession. The UK's Queen Elizabeth herself asked why had “nobody” noticed that the credit crunch was on its way, and a group of economists—experts from business, the City, its regulators, academia, and government—tried to explain in a letter. It was not just forecasting the Great Recession, but also its impact where it was clear that economists struggled. For example, in Singapore, Citi argued the country would experience "the most severe recession in Singapore’s history". The economy grew in 2009 by 3.1% and in 2010, the nation saw