『The Five Dysfunctions of a Team』要約

Patrick Lencioni's The Five Dysfunctions of a Team is a business fable that presents a model of team failure and the behaviors needed to overcome it. Published in 2002, the book is structured as a leadership story followed by a summary of the model itself. The fable centers on Kathryn Petersen, a new CEO brought in to turn around DecisionTech, a struggling Silicon Valley technology company. Kathryn inherits an executive team plagued by mistrust, politics, and unproductive meetings, and she works to rebuild how the group functions. The five dysfunctions, presented as a layered pyramid, are absence of trust, fear of conflict, lack of commitment, avoidance of accountability, and inattention to results. Lencioni argues these build on one another: without vulnerability-based trust, team members avoid honest debate; without constructive conflict, they never truly commit to decisions; without commitment, they won't hold peers accountable; and without accountability, people pursue personal status rather than collective results. At the base, trust means members admit mistakes, weaknesses, and needs for help. To address these issues, the book includes tools and exercises, such as the personal histories exercise, team effectiveness assessments, and the concepts of cascading communication and scoreboards tied to outcomes. Kathryn uses off-site meetings and pointed interventions—including a memorable exercise on conflict and the deliberate use of the team's first real disagreement—to move the group forward. The business fable format makes the abstract model concrete, while the closing section offers a quick diagnostic leaders can use to identify which dysfunction is most crippling. Lencioni stresses that the model is simple to understand but hard to sustain.