This recommended practice (RP) describes schedule contingency implementation and schedule risk management techniques to consider when developing a capital construction project execution phase schedule. AACE International recommended practices are intended to provide guidelines, not to establish standards. This RP describes general principles for applying schedule contingency in engineering, procurement and construction project schedules.

Although this RP was written as a stand-alone document it can be used as a companion with the AACE recommended practices related to schedule planning and development, risk management, forecasting, and change management. Overlapping information has been eliminated from this document in deference to the more detailed guidelines in the other RP documents.

There are a wide range of opinions regarding whether or not to allow the use of schedule contingency. This RP reflects the general consensus concerning guidelines for the proper use of schedule contingency when schedule contingency is allowed to be used.

Because the application of schedule contingency is not an area of generally accepted practice, this RP is focused on describing the schedule contingency definition, attributes and principles that professionals can generally consider for application. This RP excludes discussion of schedule risk modeling processes and analysis as well as the integrated cost and schedule risk analysis. It also excludes the detailed procedure for managing contingency through change management and other project cost/schedule control methods. AACE recommended practices have been developed to provide detailed guidelines for those related processes.

This RP describes guidelines for implementing schedule contingency as part of the overall capital project risk management process when schedule contingency is desired. These principles may be applied to any phase of a project, but become more relevant at the time of planning for project control during the execution phase. After analysis of schedule risks on the established schedule model, the project team should plan the methods to establish time contingency in the project schedule logic, and describe these procedures in the project execution and control plans.