A citizenship test is a test that may allow a non-citizen to gain citizenship of Vault City. The test challenges the applicant's Perception, Intelligence and also, a certain amount of pure blind Luck is required to pass it. A thorough medical examination disqualifies those with any visible mutations or physical defects.
At the time of Fallout 2, Proconsul Gregory carries out the tests in Vault City Council Hall. Thomas Moore is the only non-citizen thus far to pass the test. You need at least 9 PE, 9 IN, and 9 LK to pass.