This is the amount of extra budget and time we add to our project plan to match the level of risk we want on our project.
If we add an amount equal to our total RiskExposure then we are setting the level at 50%. That is, we are as likely to come in before time and under budget, as we are to come in over time and over budget.
We can use RiskMitigation to reduce our overall RiskExposure and therefore the size of our RiskReserve while maintaining the same level of risk.
As our RiskExposure evolves over time, our level of risk also rises and falls. If at a given time our RiskExposure, and therefore our level of risk, has fallen because a set of risks expired without impacting the project, we can transfer some of our reserve to a less fortunate project and still maintain our original level of risk.
See AnatomyOfRisk, RiskManagement