quota system

少し前のものですが，政治における女性の地位向上について書かれた記事から英語表現を拾います。quota自体はan official limit on the number or amount of something that is allowed in a particular period（LDOCE）とあるように「割り当てられた人数」を意味する言葉ですが，a quota systemで「｟米国用法｠（職場などに一定割合で小数民族などの受け入れを義務づける）割当制度」（『プログレッシブ英和中辞典』小学館）という意味になります。言うまでもなく，ここでの少数民族は「女性」のこと。「少数派のための割当」であることを押さえておく必要があります。（Koyamamoto）

Women for decision making
One of the big issues facing Japan is how to improve economic conditions. The situation in which Japanese women find themselves should not be forgotten. Generally women's pay is lower than men's for similar jobs.
... In its campaign for the Dec. 16 Lower House election, the Liberal Democratic Party proposed raising the percentage of women in decision-making positions to 30 percent or more in every field by 2020. This goal coincided with one the government had decided on earlier. In 2005, the government included the same goal in a Cabinet-endorsed basic plan to push gender equality. Later, the government decided to call on political parties to introduce a numerical target or a quota system for candidates in Diet elections.
http://www.japantimes.co.jp/text/ed20130107a2.html