Each academic unit has its own bylaws and mission statement, which guide the personnel, policy, and committee activities of the department. These are in accordance with the tenets of NIU Constitution and Bylaws and must be approved at the college level to take effect. Because department bylaws are upheld as legal contracts by the university, the department chairs should be familiar with the details of both their own department bylaws and those of their colleges. The mission statement is less legally binding; nevertheless, it serves the significant purpose of guiding the department's curricular and scholarly decisions and practices. Periodically both the departmental bylaws and mission statement should be reviewed and revised by the chair and faculty in order to stay current and relevant to the department's academic and disciplinary enterprise.