Philippines, Constitution 1987; accessed 17 May 2019
Section 5.1. The House of Representatives shall be composed of not more than two hundred and fifty members, unless otherwise fixed by law, who shall be elected from legislative districts apportioned among the provinces, cities, and the Metropolitan Manila area in accordance with the number of their respective inhabitants, and on the basis of a uniform and progressive ratio, and those who, as provided by law, shall be elected through a party-list system of registered national, regional, and sectoral parties of organizations.
2. The party-list representatives shall constitute twenty per centum of the total number of representatives including those under the party list. For three consecutive terms after the ratification of this Constitution, one-half of the seats allocated to party-list representatives shall be filled, as provided by law, by selection or election from the labor, peasant, urban poor, indigenous cultural communities, women, youth, and such other sectors as may be provided by law, except the religious sector.
3. Each legislative district shall comprise, as far as practicable, contiguous, compact, and adjacent territory. Each city with a population of at least two hundred fifty thousand, or each province, shall have at least one representative.
4. Within three years following the return of every census, the Congress shall make a reapportionment of legislative districts based on the standards provided in this section.
Philippines, ACT (NO. 7941) Providing for the Elections of Party-List Representatives through the Party-List System, and Appropriating Funds Therefor, Approved, March 3, 1995; accessed 17 May 2019
Section 10. Manner of Voting. - Every voter shall be entitled to two (2) votes. The first is a vote for candidate for member of the House of Representatives in his legislative district, and the second, a vote for the party, organization, or coalition he wants represented in the House of Representatives: provided, that a vote cast for a party, sectoral organization, or coalition not entitled to be voted for shall not be counted: provided, finally that the first election under the party-list system shall be held in May 1998. The COMELEC shall undertake the necessary information campaign for purposes of educating the electorate on the matter of the party-list system.
Section 11. Number of Party-List Representatives. - The party-list representatives shall constitute twenty percentum (20%) of the total number of the members of the House of Representatives including those under the party-list. For purposes of the May 1998 elections, the first five (5) major political parties on the basis of party representation in the House of Representatives at the start of the Tenth Congress of the Philippines shall not be entitled to participate in the party-list system. In determining the allocation of seats for the second vote, the following procedure shall be observed: The parties, organizations, and coalitions shall be ranked from the highest to the lowest based on the number of votes garnered during the elections. The parties, organizations, and coalitions receiving at least two percent (2%) of the total votes cast for the party-list system shall be entitled to one seat each: provided, that those garnering more than two percent (2%) of the votes shall be entitled to additional seats in proportion to their total number of votes: provided, finally, that each party, organization, or coalition shall be entitled to not more than three (3) seats.
Section 12. Procedure in Allocating Seats for Party-List Representatives. - The COMELEC shall tally all the votes for the parties, organizations, or coalitions on a nationwide basis, rank them according to the number of votes received and allocate party-list representatives proportionately according to the percentage of votes obtained by each party, organization, or coalition as against the total nationwide votes cast for the party-list system.
Philippines, Omnibus Election Code, 03 December 1985; accessed 17 May 2019