Final answer:
The best client improvement in group settings can be achieved through motivation and shared responsibility in complex tasks, small groups with strong internal cohesion and support, and effective group leaders.
Step-by-step explanation:
In group settings, the best client improvement can be achieved through several factors. Firstly, when the task is complex and difficult, individuals in the group may feel motivated and believe that their input is necessary for the group's success. This can create a sense of responsibility and commitment to perform their best. Secondly, small groups with strong internal cohesiveness and a sense of connection can provide a supportive environment for clients to improve. Finally, effective group leaders who offer incentives and rewards, and engage with group members, can also play a crucial role in overcoming collective action problems and promoting client improvement.