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Estimating Parliamentary composition through electoral polls
Author(s) -
Udina Frederic,
Delicado Pedro
Publication year - 2005
Publication title -
journal of the royal statistical society: series a (statistics in society)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.103
H-Index - 84
eISSN - 1467-985X
pISSN - 0964-1998
DOI - 10.1111/j.1467-985x.2005.00354.x
Subject(s) - composition (language) , work (physics) , general election , electoral reform , focus (optics) , computer science , econometrics , monte carlo method , statistics , political science , mathematics , law , politics , mechanical engineering , philosophy , linguistics , physics , optics , engineering , democracy
Summary. All electoral systems have an electoral formula that converts proportions of votes into Parliamentary seats. Pre‐electoral polls usually focus on estimating proportions of votes and then apply the electoral formula to give a forecast of Parliamentary composition. We describe the problems that arise from this approach: there will typically be a bias in the forecast. We study the origin of the bias and some methods for evaluating and reducing it. We propose a bootstrap algorithm for computing confidence intervals for the allocation of seats. We show, by Monte Carlo simulation, the performance of the proposed methods using data from Spanish elections in previous years. We also propose graphical methods for visualizing how electoral formulae and Parliamentary forecasts work (or fail).