Dr. Bruce Tuckman's original 1965 model of group development consisted of four stages: Forming, Storming, Norming, and Performing. In 1977, Tuckman and Mary Ann Jensen revisited the model and added a fifth stage, "Adjourning," to describe the final phase of a group's lifecycle. This stage involves the completion of the group's task and the termination of roles and relationships. It is a period of disengagement, where the focus shifts from task performance to closure, often marked by recognition of the group's achievements and a sense of loss as the team disbands.

A. Forming: This is the first stage, characterized by team orientation, introduction, and dependency on leadership.

B. Performing: This is the fourth stage, where the team is mature, organized, and functions effectively to achieve its goals.

C. Norming: This is the third stage, where conflicts are resolved, and the team establishes cohesion, norms, and standards.

E. Storming: This is the second stage, marked by interpersonal conflict, competition, and challenges to leadership and roles.

1. Tuckman, B. W., & Jensen, M. A. C. (1977). Stages of small-group development revisited. Group & Organization Studies, 2(4), 419–427. In this publication, the authors explicitly add "Adjourning" as the fifth and final stage to the original four-stage model (p. 426). DOI: https://doi.org/10.1177/105960117700200404

2. Bonebright, D. A. (2010). 40 years of storming: a historical review of Tuckman's model of small group development. Human Resource Development International, 13(1), 111-120. This peer-reviewed article reviews the history of the model, confirming the addition of the fifth stage, Adjourning, in 1977 (p. 112). DOI: https://doi.org/10.1080/13678861003589099

3. Wheelan, S. A. (2009). Creating Effective Teams: A Guide for Members and Leaders. SAGE Publications. Chapter 2 discusses various models of group development, including Tuckman's five-stage model, identifying Adjourning as the final stage.