This booklet is for people who want to improve the effectiveness of groups: group leaders, facilitators, and group members. Some of the basic factors that influence how effectively a group works together are briefly described. Factors that affect group effectiveness fall into two categories: those that affect the way group members accomplish tasks, and those that affect the way members create and maintain satisfaction with group activities. Instruments are provided to help identify areas of group performance that are working well and areas that need improvement. (Author/MLF)