Scrum recommends a team size between 5-11 members, including the Product Owner and Scrum Master. This is because the unique channels of communication between team members become too large for the team to self-organize. A larger team can create diminishing returns as new members are added. Instead of increasing your team size, consider splitting the team and adding new members until they become a large team again. Then repeat the process to scale your product development. This is known as mitosis, a recommended scaling practice to promote agility throughout the organization.