After Pill 020 where I wrote about what the Milestones are and Pill 004 where I discussed Outcome, Output and Benefit I think it is worth to clarify the difference between Milestone and Deliverable since many time they are confused on the work environment.
A deliverable is defined as any unique and verifiable product, result, or capability to perform a service that is required to be produced to complete a process, phase, or project. Deliverables may be tangible or intangible. So basically a deliverable is something required from the project charter. It may be a widget, software, or a change of some nature.
A milestone is defined as a significant event or a point in a project. Milestones are an important part of the project schedule as they help to track the progress of a schedule against a baseline.
A project has at least two milestones
- Project Start
- Project End
A milestone is something that is established to know you are on track.