Gallagher: Gallagher's disproportionality index of minimum squares - 1991 (Gcm)
Description
The Gallagher's electoral disproportionality index of minimum squares uses
a somewhat more elaborate formula than the previous indices (R, LH), for which it calculates
the differences squared between the votes and seats, adds them up and divides the result by
two and then calculates its square root. It therefore gives appropriate weight to the
distortions of disproportionality. Its mathematical formula is as follows:
$$Gcm=\sqrt{\frac{\sum(V_{i}-E_{i})^{2}}{2}}$$
for \(i = 1, 2, \ldots,n\)
Usage
Gallagher(votes, seats)
Arguments
votes
It is a vector of integers, containing the votes of all the candidates.
seats
It is a vector of integers, containing the seats obtained by each of the candidates.