A vote is not valid unless over half of the Members are in attendance and cast their votes. If the majority is a narrow one and it is obvious that one or more Members could not attend, party group chairmen may sometimes respond by asking opposing Members to absent themselves from the assembly while the voting takes place. This is done in order that the unavoidable absences of individual Members do not prevent the known will of the Althingi from being manifest in the voting. Members of the Althingi cast their vote by pressing one of three buttons on their desk. These indicate whether the Member is for or against a matter, or abstains from voting.
Voting can take place with the raising of hands.
Members can request that the president call the roll and ask each individual Member whether he or she is for or against. When voting is carried out electronically or by roll call, the Members have the opportunity of making a short explanation for their position. If the president expects all Members to be in agreement on a certain question he may declare that it will be brought to a conclusion without a vote if no one objects. This procedure is generally used on points of order rather than matters of substance.