A very quick answer on this question about the difference between PBS and WBS could be : "a PBS is a Product Breakdown Structure and comes from PRINCE2, while a WBS is a Work Breakdown Structure which comes from PMI".
However, there is more to say about this difference !
I recently followed a conversation on Linkedin where this question popped up. Many of my colleagues replied with some plain theory or from their own experience.
I personally find the explanation from Stefan Ondek, PMP the most correct and the best in clarifying the difference between PBS and WBS. Here is what he wrote :
"PRINCE2 in the new 2017 version uses the terminology in the following way:
- A product breakdown structure is a hierarchical breakdown of the products to be produced during a plan; in PRINCE2 a product breakdown structure contains just products.
- A work breakdown structure is a hierarchical breakdown of the entire work that needs to be completed during a plan; in PRINCE2 a work breakdown structure contains just activities.
The PMI’s PMBOK (Project Management Institute, 2013) defines a work breakdown structure as: ‘A deliverable-oriented hierarchical decomposition of the work to be executed project team to accomplish the project objectives and create the required deliverables, organizes and defines the total scope of work.’
Users of PRINCE2 from a PMI background might find it useful to substitute the phrase ‘product-oriented work breakdown structure’ when they see product breakdown structure in the PRINCE2 manual."
"Importantly, both uses of the terminology agree that project managers need to plan by breaking down the products or outputs of the project first and, only then, break the activity needed to produce the products."
This illustration from Patrick Roose, also gives a more clear view on the difference between PBS and WBS.
ProjectManager.com has published The Ultimate Guide to Work Breakdown Structure on their website to explain the WBS concept in further detail. Just folow the link to learn more about a WBS.
I wrote another (Dutch) blog article in 2012 about the use of a WBS while describing your project idea during the project initiation phase.