Missing a milestone might be the worst thing that can happen to a project. A milestone defines the completion of an important step in a project’s development process and task times are often dictated by it. If a milestone is missed, the first step for the project manager is to identify why. In terms of the Gantt chart: Was the milestone deadline too early and the balloon popped because there was not enough R & D? Was hiring done too quickly and the right skill set was not hired? Where there too many vacations and less time spent on the project? Where tasks changed among workers? Was there not enough time spent on acquiring funding and there are not enough/poor quality resources/vendors? As time is the running theme among all these possibilities the easiest solution is to extend the completion deadline. If deadlines are beyond control, compromises would have to made on the result of the project. Negotiations would have to been done between the customer and the company, and if it is internal, between the company and its employees.