One of the mandatory eligibility criteria is: passing relevant examinations for gaining a post in the department. Candidates have to pass a number of tests for ensuring competence. They need to pass written examinations, often conducted by police academies. A majority of police departments also test candidates on factors like strength, speed, vision, and hearing. Some law enforcement units perform background or psychiatric interviews for evaluating any particular recruit's individual characteristics as well as general suitability for holding a law enforcement post. Lastly, a majority of candidates also have to pass lie detector and drug tests.
