Although championed by advocates of proportional representation, the s
ingle transferable vote form of PR has been used consistently in only
a small number of countries - principally Australia, Ireland and Malta
. This paper examines the origins and development of STV and its impli
cations for the political systems that use it. The results show that S
TV varies so widely in its form and application, differing on no less
than five major characteristics, that it is impossible to identify any
single generic type. These differences are also reflected in the part
y strategies that are used to maximize the vote under STV. A regressio
n analysis of the various types of STV shows that Malta is the most pr
oportional system, followed by Ireland and Tasmania. Ireland has the l
argest party system among the countries that use STV, net of other fac
tors.