This recommended practice is intended to provide a guideline, not establish a standard. This is not a how-to on any particular methodology.

As a recommended practice of AACE International, development of activity logic (also called network logic) in planning and scheduling provides guidelines for the sequencing of activities in a logical way generally before duration estimating can be performed. Logic is generally determined before durations are considered. Logic development methods include precedence diagramming, or arrow diagramming methods. Logic is the set of activities and dependency relationships between them. Logic dictates the planned sequencing of activities. A network diagram is often used to illustrate the logic.

Planning and scheduling are not the same. Planning is determining how the work will be done, while scheduling is the analysis and calculation of start and finish dates.

Logic enables the combination of activities to be arranged in one of the aforementioned formats so that a completion date can be established. Logic also enables backward passes to arrive at optimal overall schedule duration.

This recommended practice is for use by project team members involved in planning process, a continuation of activity identification process. As in identification of activities, many individuals contribute to the development of activity logic. Having an experienced planner coordinate the process improves final quality, and adds value to the planning process.