Forecasters are often met with skepticism. Almost every time I tell someone that I work in forecasting, they say something about forecasting the stock market, or forecasting the weather, usually suggesting that such forecasts are hopelessly inaccurate. In fact, forecasts of the weather are amazingly accurate given the complexity of the system, while anyone claiming to forecast the stock market deserves skepticism. So what is the difference between these two types of forecasts, and can we say anything about what can be reasonably be forecast and what …