what are contingency costs
AACE International, the Association for the Advancement of Cost Engineering, has defined contingency as An amount added to an estimate to allow for items, conditions, or events for which the state, occurrence, or effect is uncertain and that experience shows will likely result, in aggregate, in additional costs.hese uncertainties are risks to the project. Some refer to these risks as known-unknowns because the estimator is aware of them, and based on past experience, can even estimate their probable costs. The estimated costs of the known-unknowns is referred to by cost estimators as cost contingency.