By arrangement between parties in the Senate, a system of pairing operates, whereby a senator who is absent and who is expected to vote on one side in a particular question is "paired" with a senator who is expected to vote on the other side and who is either also absent or who deliberately does not vote in order to cancel out the effect of the other senator's absence. Pairs are also arranged for vacant places in the Senate. This system ensures that the result of votes is not determined fortuitously by the absence of particular senators. Pairs are usually not arranged, however, for secret ballots, for the reason that voting is meant to be secret and it should not be known how individual senators vote.
Pairing arrangements are determined by the party whips, and may last for days, weeks or months, or may be varied from vote to vote. Pairs are entirely an informal arrangement between the parties and not part of the procedures of the Senate. The chair therefore does not consider any matters relating to pairs. In earlier years rulings were made to the effect that pairs could not be referred to in the course of proceedings. These rulings are now not followed, and it is common for senators to make statements concerning pairing arrangements. This practice has been upheld by a President's ruling. Pairs are not referred to in the Journals record of votes, but lists of pairs are included in the voting lists shown in Hansard.