Party nationalization score is a measure for the uniformity of vote share of a party over subnational units (provinces for Ecuador). It is computed as 1 minus Gini inequality index (Jones and Mainwaring, 2003)
$$PNS = 1 - G$$
$$G = (2*sum(i*xi)) / (n*sum(xi)) - (n + 1)/n$$
in which G is the Gini inequality index,
xi is the vote share in the province ith, indexed in non-decreasing order (xi <= xi+1)
i is an index from 1 to n
n is the total of provinces
Party nationalization score is a number from 0 to 1, a low value (near 0) means a low level of nationalization, i.e. heterogeneous distribution of vote shares in subnational territorial units.
High score (near 1) indicates a high level of nationalization, i.e. homogeneous distribution of vote shares in subnational territorial units.
A new approach developed by Golosov (2014) 'Party System Nationalization: The Problems of Measurement with an Application to Federal States' (http://ppq.sagepub.com/content/early/2014/09/08/1354068814549342.abstract) is also available.
See psns function for further information.
Developed by Jorge Albuja Delgado (albuja@yahoo.com).