In paper ballot voting the voter can in general make two kinds of voting errors: First of all voters may write the wrong number on ballot simply because they do not remember the correct number. Secondly, it may be that the voter is not aware of the fact that in municipal elections it is only possible to vote for the candidates in the voter’s municipality of residence. The voter may want to vote for a candidate nominated in another municipality. In this case the vote goes to the candidate in the voter’s municipality of residence, who happens to have the same number than the candidate in the other municipality, who the voter actually wanted to vote for.
In paper ballot voting the voters can not in any way confirm their choice, so they may end up voting for someone else than they intended to vote for. In most cases the voters are not even aware of their mistake.
Electronic voting reduces the risk for above mentioned mistakes notably: when the voter enters the number, the identification information of the chosen candidate will appear on the screen. This way the voter can make sure he or she is about to vote for the correct candidate.
In electronic voting it is not possible to draw inappropriate pictures on the ballot and the problem with unclear ballots will no longer exist. This means that the number of invalid votes will decrease significantly. However, it is still possible to cast a blank vote.