This is a sample Contingency Drawdown Curve. It shows the original contingency baseline (blue) and the use or consumption of the contingency (purple). The red curve shows the remaining contingency by subtracting the usage from the original total contingency. the green curve shows the revised projected use of the remaining contingency. This format provides a synoptic overview of the project's contingency, updated whenever some of the contingency is used. It's a great forecasting tool to determine if the remaining contingency is still adequate. The shape of the original baseline contingency should be determined by a risk analysis (or expert judgement).