The core team is the engine of our race car. All the driving and lubrication in the world is no use without an engine. The core team executes the Product Owner’s vision with the help of the ScrumMaster. The team is comprised of the people needed to deliver the work –developers, testers, architects, designers – anyone who is needed. A core team is ideally made up of full-time people dedicated to the project. The team is responsible for managing its work, its commitments and the execution of those commitments.
Most Scrum material will say that the ideal team size is seven, plus or minus two people. I prefer even numbers as it facilitates better XP engineering practice integration. The team is just that, a team – roles and titles should be removed as it helps build the camaraderie around the team. The goal is to remove the mindset of “I’m a developer and I only write code” and shift the attention to “I’m a team member who is responsible for delivering this work and I cannot do it alone” – enter the team. On a Scrum team, testers may write code and developers may write tests – cross functionality is a good thing.