The PMBOK Guide defines the project scope as "the work that needs to be accomplished to deliver a product, service, or result with the specified features and functions." Accordingly, the project scope includes the scope of the product, service, or result, which is defined as "the features and functions that characterize the product, service, or result."
Basically, project scope is the quantity of all necessary activities that are obligatory for the approval of the project by the customer/contractee. Therefore, project scope (the how) includes the product scope (the whats).
In traditional project management, the project scope is detailed in the work breakdown structure e. g. in a Gantt-chart, which is part of the project plan.
Deviations from the defined project scope during the project execution may lead to higher cost or delays in deadlines. This development is called scope creep. It is common that in the course of a project changes need to be made to the project scope, either because requirements of the product (service or result) change or due to other changes in resources for example.
In agile project management, changes to the project scope are seen as part of the learning process in the course of the project. Adapting changes in scope are an incremental part of the agile approach to project management as the goal is to constantly improve the product, service, or result.
Nevertheless, scope creep of any kind can have derailing effects in certain industries, e. g. manufacturing, where a finished product needs to be delivered within budget and time to fulfill the order.