Once the project is executing, all of the project management processes are integrated in the schedule. The integration occurs here because of an overriding philosophy “what’s in the schedule gets done”. In other words, all of the work of the project should be in the schedule and if an activity is not in the schedule, it should not be worked on.
The schedule is the focal point of managing the project, and all the project management processes are integrated in the schedule. You should have activities and time allocated in your schedule for communicating, managing scope, updating the schedule and all other project management activities. The integration occurs when the project management processes touch each other, as well as when the project management and project lifecycle activities overlap. Consider the following examples:
A large scope change request is approved, resulting in more work. This is a typical integration of project management and project lifecycle work. The impact is reflected in the updated schedule.
You identify risks and create a Risk Management Plan to manage the risks. You communicate the resulting Risk Management Plan to all interested stakeholders for feedback. This is an integration of managing risk and managing communication. Since all of this work takes time and effort, the activities are on the schedule.
You have an issue with poor quality. The issues management process is invoked and all appropriate corrective activities are added to the schedule. To resolve the problem, you decide to collect more metrics and the metrics-collection activities are added to the schedule. The analysis of the metrics results in changes to your work processes and additional quality-control activities. You are communicating to all management stakeholders to manage expectations. All of this work will be reflected in your schedule.
All project work should be reflected in the schedule. Therefore, this step is where the project is managed and controlled, and it is the place where all of the project life cycle and project management activities are executed, tracked and integrated.
In the PMBOK Guide, a separate Knowledge Area is created to manage the integration of all project management and project lifecycle work.