We see from the table that the base rates are very different for different project types for both mean risk and tail risk. The highest mean risk is found for nuclear storage, at 238 percent, while the lowest is found for solar power, at 1 percent. The highest risk for ending up in the tail is held by the Olympics, at 76 percent, while the highest mean overrun in the tail is found for IT projects, at 447 percent. Differences in base rates must be taken into account when planning and managing projects but often are not. Frequently, empirical base rates are not considered at all.
