The Party-List System Act, or Republic Act No. 7941, provides for the election of party-list representatives.

Enacted in March 1995, the law aims to ?enable Filipino citizens belonging to the marginalized and underrepresented sectors, organizations and parties ... to become members of the House of Representatives.?

The act defines the party-list system as a ?mechanism of proportional representation.? Section 11 of RA 7941 says that party-list representatives ?shall constitute twenty percentum of the total number of the members of the House of Representatives, including those under the party-list.?

The law also mandates that only party-list organizations garnering at least 2 percent of the total votes cast nationwide for the party-list system shall be entitled to one seat each.

It also says that each party shall be entitled to a maximum of three seats, and that the allocation of seats will be proportional to the total number of votes.

Controversy, however, has surrounded the allocation of seats among the elected party-list groups.

During the 2007 elections, the Commission on Elections announced that only the top party-list group would get the maximum three seats. The Comelec invoked the so-called ?Panganiban formula? that appeared in the October 2000 Supreme Court decision, ?Veterans Federation Party et al. vs Comelec.? It was penned by former Chief Justice Artemio Panganiban.

Using this formula, if the topnotcher party obtains at least 4 percent but less than 6 percent of the total votes cast, it gets one more seat. If it garners 6 percent or more, then it gets the maximum two additional seats.

Additional seats to be given to the rest of the qualified parties were to be ?proportionately? computed in relation to the total number of seats and votes garnered by the top party-list group, according to the formula.

Following this, only pro-life group Buhay Hayaang Yumabong (Buhay) got three seats following the 2007 elections. This caused an uproar among other party-list groups, particularly Bayan Muna, Gabriela, Akbayan and Anakpawis.

There are currently 16 party-list groups occupying 22 seats in the 14th Congress. They make up just 9 percent of the 238 members of the House. Only four groups?Apec, Bayan Muna, Cibac and Gabriela?are holding two seats each.

Despite criticisms against the Panganiban formula, the high court unanimously upheld it in subsequent decisions??Partido ng Manggagawa vs Comelec? (March 2006) and ?Cibac vs Comelec? (April 13, 2007). Inquirer Research