Project scope is a combination of product functionality, project resources, and available time.
Brooks' law states that adding labor to a late software project makes it even later.
If the effort required to implement the system features is equal to the resources available during the scheduled time, the project has an achievable scope.
Overscoped projects are typical. In many projects, it will be necessary to reduce the scope by as much as a factor of two.
The first step in establishing project scope is to establish a high-level requirements baseline.