Postal voting is voting in an election where ballot papers are distributed to electors (and typically returned) by post, in contrast to electors voting in person at a polling station or electronically via an electronic voting system. In an election, postal votes may be available on demand or limited to individuals meeting certain criteria, such as a proven inability to travel to a designated polling place. Most electors are required to apply for a postal vote, although some may receive one by default. In some elections postal voting is the only voting method allowed and is referred to as all-postal voting. With the exception of those elections, postal votes constitute a form of early voting and may be considered an absentee ballot. Typically, postal votes must be mailed back before the scheduled election day. However, in some jurisdictions return methods may allow for dropping off the ballot in person via secure drop boxes or at voting centers. Postal votes may be processed by hand or scanned and counted electronically. The history of postal voting dates back to the 19th century, and modern-day procedures and availability vary by jurisdiction. Research, focused on the United States and using data from states where postal voting is widely available—California, Oregon and Washington—shows that the availability of postal voting tends to increase voter turnout. Electoral laws typically stipulate a series of checks to protect against voter fraud and allow for the integrity and secrecy of the submitted ballot to be maintained. Known instances of fraud are very rare. Coordinated, large-scale fraud by postal voting is likely hard to pull off undetected because the large number of interested parties (such as officials, political operators, and journalists) as well as a large number of scholars and analysts who are capable of detecting statistical outliers in vote totals signifying large-scale fraud. Officials can confirm instances of fraud by checking signatures and conducting basic detective work. All-postal voting All-postal voting is a form of postal voting in which all electors receive their ballot papers through the post, not just those who requested an absentee ballot. Depending on the country, electors may have to return their ballot papers by post or they may be allowed to deliver them by hand to specified drop-off locations. All-postal voting is used in several states in the United States and in Switzerland, and was used in 2016 in the Australian Marriage Law Postal Survey