The development of a project plan is often an optimization process. Therefore it may require several iterations to establish an acceptable plan. Every project activity has risk in it. The planning process needs to balance the risks in a way to minimize risk on high priority items from the project charter, and take greater risk on lower priority items. This optimization revolves around the "triple constraint" of project management: scope management, schedule management, and resource/budget management.
To assist project teams in planning and control, numerous project management methodologies have been created. There purpose is to help the project team and the business leadership make sense of the work that must be done, prioritize it correctly, and set reasonable expectations for it will take to reach the project goal.
Tollgate/Phasegate Planning
Tollgate planning, also known as Phasegate planning, is used in order to control high project risk. Tollgate planning divides the project tasks into phases. Each phase is structured around being able to resolve a major risk issue on the project. The phases are then ordered so that risks are addressed in a manner that minimizes the impact on later phases. Once all the tasks for a phase have been identified, the tasks are then budgeted and scheduled for that phase. Often the detailed tasks of a later phase can not be identified until an earlier phase is complete.
The Tollgate planning approach is excellent for managing risk because as each phase completes, a business decision meeting, called a Tollgate, is scheduled. The project team and appropriate stakeholders meet and review the results of the work from the preceding phase to determine whether the risk has been adequately mitigated. One of three project options is selected by those at the meeting. The first option is to continue on to the next phase since the risk has been adequately mitigated. The second option is selected when the risk has not been adequately mitigated. In that case the decision is to conduct additional activities beyond what were originally planned for the phase. These additional activities are designed to mitigate the risk. This entails a rebaseline of the project with appropriate adjustments to project end date and total budget. The third option may be selected whether the risk has been mitigated or not. This option is to cancel the project. Either the business needs have changed, or the activities needed to resolve the risk are more than the business is willing to undertake. In those cases, the project is canceled and the resources are released to work on other projects.
Phase/Tollgate Scheduling Technique:
Identify the key project risk milestones
Sequence the risk milestones to minimize overall project risk
Identify the tasks needed to resolve each of the risk milestones. This does not need to be accomplished until preceding milestones have been completed
Create a schedule (network diagram or Gantt) of the tasks supporting each of the milestones. This does not need to be accomplished until the activities for that phase are about to begin.
Conduct tollgate meetings at appropriate points in the project and decide to continue, rebaseline, or cancel the project.