Several factors influence the effort group members expend on tasks. These include task design, reward systems, and group interaction processes. Task design has a large impact on motivation if the task is clear and important. Reward systems can also motivate members if they provide incentives for group output. However, as group size increases, individual effort tends to decrease due to less interaction. A group's composition and members' knowledge/skills also impact performance. Ensuring members have relevant expertise optimizes efforts.