Scrum teams are not hierarchical organizations. Rather, everyone collaborates to complete the development work the team has committed to performing during a given sprint. Individuals do not have assigned roles, but instead work together for the greater good.
Most Scrum teams have between five and nine members, but this varies. Larger projects are accomplished through the practice of scaling, like having Scrum teams within Scrum teams. When structured properly, such scaling can accommodate more than 1,000 people. Within this structure, each team sends one person to a “Scrum of Scrums” meeting where inter-team work is coordinated. These meetings usually occur a few times per week, but not every day as the team meetings do.