Project Scope vs Product Scope
The official PMI definition that you will find in many PMI standards publications is that
Product Scope: is the features and functions that characterize a product, service, or result.
Project Scope: is the work performed to deliver a product, service, or result with the specified features and functions.
But in a nutshell, product scope is the product specification. At the end, we will need this again to validate whether the project met its objectives by comparing the end product with the specification. Product scope is what remains after the project is done.
Project scope is all the project work including the project management work needed to achieve the product scope. Note that there are different ways to achieve the product scope and hence the project scope can be different for the same product scope based on the choices made by the project management team and the project constraints. Project scope exists and is in focus while the project is in progress but not after the project is done. Once the project ends, we only see and experience the product scope.
Purpose: Why should we make this distinction? By calling out the product and project scope separately, it allows us to ensure we are not missing anything. By thinking about just what we get when the project is done, it’s easy to miss crucial components of work as we will see in the example above. This neglect of identifying critical project work typically leads to schedule slippage and quality problems due to improper identification of the appropriate resources to build the product.
You meticulously define the features and functions (aka product scope) of a house you want to buy for your family but you don’t put much thought into researching the work that needs to go into the purchase of a house. The resulting problems could include:
If it is a custom home, you may have neglected to account for the time it takes to get inspectors to sign off on your house.
If it is a new construction tract home, if you aren’t familiar with the builder’s process before closing (like third party inspection, homeowner walkthrough, etc.), you may have find yourself out of time missing the critical homeowner walkthrough (perhaps you check off the box by doing a virtual tour) and fail to identify a critical foundation issue and accept the home at closing thereby losing the opportunity to get an expensive problem fixed by the builder for free.
If it is an existing home, similarly if you are unfamiliar with the risks associated with third party inspections, you may not have the necessary checks and balances and end up with an inspector that misses a crucial defect with the pool pump and find yourself having to replace this $3,000 item on your first day at this new house (true story).
A lot of times, understanding this distinction will help you uncover risks you may not have otherwise identified along with properly identifying the qualifications of key resources.
On the exam, you may not see a direct question on these differences but these concepts are building blocks to understanding future topics like deliverables in the Project Scope Statement and their eventual decomposition in the WBS. Also, if the terms appear in one of the choices of a multiple choice question on the exam, having a basic understanding of the definitions could help you decide whether to leave the choice for further consideration or eliminate it.