Spanish to English Marketing Marketing Consultancy

The term appears in a context of a simulation for Spain's next general elections according to current vote intention. In this paragraph:

"Podemos, con el 27,7% de los votos, podría obtener un 33,1% de los escaños, o sea casi un tercio de los diputados. Este efecto desproporcional, parte constitutiva de la mecánica del sistema electoral español, beneficiaría en este caso también al PSOE (26,2% de los votos y 31,1% de los escaños) y al PP (20,7% de los votos y 24,9% de los escaños). Los 3 partidos obtendrían un 5% más de escaños como premio adicional con respecto a sus votos."

This is how I see it:

"Podemos, with 27.7% of the vote, could obtain 33.1% of the seats, or nearly one third of the deputies. This disproportionate effect is a constituent part of the mechanics of the Spanish electoral system. This effect would also benefit the PSOE (26.2% of the votes and 31.1% of the seats) and the PP (20.7% of the votes and 24.9% of the seats). Therefore, the three parties would get a 5% seat increase as an additional prize with respect to their share of votes."