An absentee ballot is a vote cast by someone who is unable to attend the official polling station to which the voter is normally allocated. Methods include voting at a different location, postal voting, proxy voting and online voting. Increasing the ease of access to absentee ballots is seen by many as one way to improve voter turnout through convenience voting, though some countries require that a valid reason, such as infirmity or travel, be given before a voter can participate in an absentee ballot. Early voting overlaps with absentee voting. Early voting includes votes cast before the official election day(s), by mail, online or in-person at voting centers which are open for the purpose. Some places call early in-person voting a form of "absentee" voting, since voters are absent from the polling place on election day.