Monitoring and Controlling the Project

In PMBOK’s phases of project management, the third phase (Execution) and the fourth phase (Monitoring and Controlling) often feel as though they are one and the same. But, make no mistake – they are not, no matter what methodology you are using.
Although, they are tied extremely close together. In fact, it’s sometimes necessary when you reach Phase four to return to Phase two and begin planning again. However, it’s probably more realistic to look at phase three and four this way:
In Phase three, you execute your original project plan. But, it’s pretty rare that all of your project tasks are happening simultaneously. So, it’s quite possible that while you’re executing Task 2 (Phase 3), you’re monitoring Task 1 (Phase 4) to make sure the work is going according to the project plan (Phase 2).