What is the correct number of Product Backlogs when multiple teams are working on the same product?

When multiple teams are collaborating on the same product, the correct approach is to maintain only one Product Backlog for the entire product. This practice ensures that all teams are aligned and have a single source of truth regarding the work that needs to be accomplished. A unified Product Backlog helps in prioritizing features and requirements consistently, facilitating transparency and collaboration among teams.

Having one Product Backlog allows for better coordination of efforts, as different teams can work on different items from that backlog while still contributing to the same overall project goals. It also aids in the management of dependencies between teams, as they can see how their work interrelates and identify any need for collaboration.

In contrast, having multiple backlogs could lead to misalignment, confusion about priorities, and difficulties in understanding the overall progress of the product. This could potentially create silos within the teams, hindering communication and the ability to deliver a cohesive product. Hence, maintaining a singular Product Backlog is a foundational element of Scrum that supports effective scaling and teamwork across multiple teams working on the same product.