Formal and informal work groups are becoming increasingly important competitive factors in organizations. Teamwork is the result of groups working together to effectively and efficiently achieving organizational goals. Formal groups include command and task groups. Informal groups include interest and friendship groups. A useful way to analyze groups is to view them as systems that use inputs, engage in various processes or transformations, and produce outcomes.work groups by weighing the characteristics of members they assign to particular groups. Group members should have task-relevant expertise and appropriate interpersonal skills. Also, it has been found, that a degree of diversity among group members usually adds to performance. Group training, particularly for diverse groups, has been found to be usefulMembers may be attracted to a group for a number of reasons including being attracted to or liking other members of the group, liking the activities of the group, the goals or purposes of the group, because the group satisfies an individual’s need for affiliation, and/or because the group can help an individual achieve a goal outside the group. The absence of attraction can prevent the group from achieving high performance. Member roles in groups include group task roles, group maintenance roles, and self performance. Member roles in groups include group task roles, group maintenance roles, and self oriented roles. The size of the group has also been found to have significant bearing on the group’s performance. Mid-sized groups, from five to seven members, seem to be an optimum size according to recent research. Smaller groups can often exacerbate individual differences.Large groups tend to be when working in groups than when working alone. Free riding is particularly likely when members exhibit individualism rather than collectivism. Managers can combat social loafing by several methods. Assign just enough people to do the work is one key method. Other methods include making each individual’s work visible, providing for individual feedback, have people work with those the respect, have standards to actually measure group performance, and making rewards contingent on a combination of individual and group performance.