For example, a conceptual estimate may have a contingency of 20% and an allowance of 10%, while a detailed estimate may have a contingency of 5% and an allowance of 2%. However, these percentages are not fixed and may vary depending on the project characteristics and the level of confidence of the estimator.
The contingency allowance is the time allocated during planning for unscheduled events. Technical and personal disruptions result in changes in the indirect production costs. The contingency allowance is calculated in special contingency time studies, the results of which yield rates for indirect production costs.