This recommended practice (RP) for determining activity durations is intended to provide a guideline and a resource, not to establish a standard. As a recommended practice of AACE International, it provides guidelines for the project scheduler to determine schedule activity durations and understand the limitations and assumptions involved in such determination as part of the total cost management (TCM) project planning, scheduling forecasting, and change management processes.

This recommended practice provides information about determining the original durations for activities for developing the project schedule and general considerations related to the establishment of remaining durations while updating the project schedule. Specific considerations regarding the topic of establishing the activities remaining durations for schedule performance assessment are not within the scope of this RP. Therefore the information presented here generally applies to determining original activity durations; and general considerations for the establishment of remaining durations be provided only as appropriate.

This recommended practice offers methods for determining original activity durations through the analysis of past project data with anticipated future performance data. It also incorporates an iterative effect-analysis of constraints on activity duration.