Ordinarily, every ballot paper in an election is identical, with the candidates' names and their party groups (if any) in the same order. Within the party or group ticket, the order of their candidates' names is decided by the group. The order of the groups on the ballot is usually determined by lot, by the authority running the election.
Having all ballot papers the same can give a slight advantage to the candidate or group listed at the top, or top left, of the ballot paper (depending on the format of the paper), because they will attract a donkey vote. Donkey voters thoughtlessly number the preferences on their ballots from left to right and/or top to bottom, purely in the order of the candidates' names and groups on the ballot.
Such voters are a feature of voting systems which require people to express their degree of preference for every candidate, by numbering in preferential order, or have their vote declared invalid. While donkey votes may only form a small percentage of votes cast, they could affect the result in a close contest. The more candidates there are on the ballot paper, the higher the donkey vote is likely to be.
To eliminate any donkey vote advantage, the Robson Rotation method requires ballot papers to be printed in equal-sized batches, with each batch having a different candidate's name appearing at prescribed positions in the party columns on those ballots. As a consequence, there are a number of possible permutations of where candidates' names appear on the various version of the ballot paper. While that doesn't eliminate donkey voting, it spreads its effect more-or-less equally to all the candidates standing for election.
The method was introduced in the Australian state of Tasmania by Neil Robson, Liberal MHA for Bass, and first used in the Denison state by-election, 1980. It was adopted in Australian Capital Territory elections in 1995.
Kromkowski rotation in Indiana
In the 1970s in St. Joseph County, IN; a similar kind of ballot rotation was introduced. The method of ballot printing and for use in lever operated machine voting was developed and introduced by Aloysius J. Kromkowski, the head of the election commission, and one of the most popular elected officials (St. Joseph County Clerk until term limited and St. Joseph County Treasurer until term limited.) Every precinct had alphabetically shifted ballot. So for example, in precinct 1, the ballot would be in standard alphabetical order. In precinct 2, the ballot would start with the second alphabetically ordered candidate and the first ordered would be shifted to the bottom; etc.
It was later codified into law via Indiana Code P.L.3-1987, SEC.327.
- Robson, Neil (2004), Everybody counts : Tasmania's unique electoral system Hare-Clark with Robson Rotation, Government Printer?, retrieved 19 December 2013
- Tasmanian Parliamentary Library - House of Assembly Elections
- ACT Electoral Commission - Ballot Papers for the Legislative Assembly