The action component of the PYP can involve service in the widest sense of the word: service to fellow students, and to the larger community, both in and outside the school. Through such service, students are able to grow both personally and socially, developing skills such as cooperation, problem solving, conflict resolution, and creative and critical thinking. Moreover, these actions are ways in which the students exhibit their commitment to the attributes of the learner profile and to the attitudes that we seek to engender within the PYP classroom. In fact, the actions that the students choose to take as a result of the learning may be considered the most significant summative assessment of the efficacy of the programme.
Making the PYP happen: A curriculum framework for international primary education p. 25.