A Hybrid VNS/Tabu Search Algorithm for Apportioning the European Parliament

  • Gabriel Villa
  • Sebastián Lozano
  • Jesús Racero
  • David Canca
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3906)


In a Proportional Representation (PR) electoral system it is assumed that seats are apportioned to the different electoral districts/states according to the corresponding voters’ distribution. In a previous paper we proposed a MILP (Mixed Integer Linear Programming) model to apportion the seats in the European Parliament (EP). Since the exact solution to the problem is not computationally efficient, we have designed a hybrid metaheuristic algorithm based on Variable Neighborhood Search (VNS) and Tabu Search (TS). The proposed approach takes into account the existing situation, guaranteeing a minimum number of seats, independently of the population size of each member. The model is illustrated with actual data and its results are compared with the present apportionment. The results show that the proposed approach can significantly improve the proportionality of the present apportionment.


Data Envelopment Analysis Tabu Search Electoral System Variable Neighborhood Search Proportional Representation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Gabriel Villa
    • 1
  • Sebastián Lozano
    • 2
  • Jesús Racero
    • 1
  • David Canca
    • 1
  1. 1.University of SevilleSevillaSpain
  2. 2.University of Seville, E.T.S. Ingeniería InformáticaSevillaSpain

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