Working Groups conduct the majority of the actual research that occurs in the IMCI Collaboratorium. And actively participating in Working Groups is the predominant way that people participate in the IMCI Modeling Core. We encourage teams to cross disciplinary and hierarchical boundaries, thus creating a unique combination for connection and networking. Currently, Working Groups tend to be about half faculty and the other half a mixture of postdocs, students and technicians. These meetings are work sessions and task-oriented. Working Groups are not intended to be permanent but rather fluid with shifting focus and membership, as needed.