 The second main specification problem involves time frames. Many distributive principles identify and require that a particular pattern of distribution be achieved or at least be pursued as the objective of distributive justice. But they also need to specify when the pattern is required. One version of the principle of strict equality requires that all people should have the same wealth at some initial point, after which people are free to use their wealth in whatever way they choose, with the consequence that future outcomes are bound to be unequal. Principles specifying initial distributions after which the pattern need not be preserved are commonly called ‘starting-gate’ principles. (See Ackerman 1980, 53–59,168–170,180–186; Alstott and Ackerman 1999.)