In my view, the purpose of a project management maturity model has several purposes: 1) allow the Project Manager and their team to separately think about and discuss which project management tools, processes and practices are most important for them and their customers. 2) If the PM and the team members use the model separately to assess the maturity of the identified most important tools, processes and practices (maturity attributes), they can get a feel for perception and communication gaps within the team. 3) The model should be used to first identify where the team and the PM think they are today, and to set a goal for where they think they want to be in the future. Understanding gaps between current state and future state desired sets the stage for improvement plans, prioritization, and resource allocation. 4) The right level of maturity is not always the maximum (I'm thinking of maximum as level 5 on a 1 to 5 scale). The team, in consideration of their needs and resource means, must decide what maturity level for each attribute is right for them. 5) Finally, when problems are occurring in a project and the PM and team can't quite put their finger on the causes or corrective actions, the maturity model can help them with a self-diagnosis, or it can be used by an objective 3rd party assessor to help them with a diagnosis.