A candidate for parliament must be a citizen of Tuvalu of a minimum age of 21 years. Voting in Tuvalu is not compulsory. At 18 years of age, Tuvaluans are eligible to be added to the electoral rolls. The parliament has 15 members, each of whom serve a four-year term. Each member is elected by popular vote in one of eight island-based constituencies: seven islands elect 2 members each, while Nukulaelae is represented by 1 member. The residents of Niulakita, the smallest island, are included in the electoral roll for Niutao.