Project scheduling can be approached in a number of different ways depending on the granularity and detail required.
The most detailed approach consists of going down to the activity level, let us say, what as less as one person can develop in as much as a week. This schedule can not be reported as such to management and a higher level view must be prepared. It will describe project schedule in terms of phases, stating start and end dates for each relevant phase of the project. This way, we will have a good picture with regards by when resources will be needed and by when the deliverables linked to every phase will be completed.
For senior management, sometimes, it is again, too detailed as they want to track events like when the project will be completed or when the resources can be released to be utilized for other projects.
This brings us to the milestone based schedule, where only a few – up to five – dates are reported. Some examples could be: products delivered, project closed, project initiated, products ready for test and so on.