All electoral systems have thresholds of representation: that is, the minimum level of support which a party needs to gain representation, either legally imposed (formal), or merely mathematically de-facto (effective). In some cases, these thresholds are a by-product of other features of the electoral system, such as the number of seats to be filled and the number of parties or candidates contesting the election, and are thus categorized as 'effective' thresholds. In other cases, however, these thresholds are written into the electoral law, which defines the PR system, and are therefore 'formal'.
In Germany, New Zealand, and Russia, for example, there is a five percent threshold: parties which fail to secure five percent of the vote are ineligible to be awarded seats from the PR lists, see Germany: The Original Mixed Member Proportional System, see New Zealand: A Westminster Democracy Switches to PR, and see Russia - An Evolving Parallel System. This provision had its origins in the German desire to limit the election of extremist groups, and is designed to stop very small parties from gaining representation. However, in both Germany and New Zealand there exist 'back-door' routes for a party to be entitled to seats from the lists; in the case of New Zealand a party must win at least one constituency seat, and in the case of Germany three seats, to by-pass the threshold requirements. In Russia in 1995 there were no 'back-door' routes, and almost half of the party-list votes were wasted.
Elsewhere, legal thresholds range from 0.67 percent in the Netherlands to 10 percent in the Seychelles, see The Netherlands. Parties, which gain less than this percentage of the vote, are excluded from the count. In all of these cases the existence of a formal threshold tends to increase the overall level of disproportionality, because votes for those parties who would otherwise have gained representation are wasted. In Poland in 1993, even with a comparatively low threshold of five percent, over 34 percent of the votes were cast for parties, which did not surmount it, see Poland: Between Fragmentation and Polarisation. But in most other cases thresholds have a limited effect on overall outcomes, and some electoral experts therefore see them as unnecessary and often arbitrary complications to electoral rules, which in most cases are best avoided.
