  Criteria for a good voting system have been given particularly careful
scrutiny in recent years, with general agreement that the core values are fair
results, voter power and choice, and local representation.
  This paper reexamines the basic ideas of three widely used voting systems,
the Single Transferable Vote, List-PR, and Mixed Member Proportional (MMP); and
evaluates their performance in terms of both principles and practice.
  It looks particularly closely at proportionality, examining three aspects:n
linearity, the threshold for representation and the threshold for gaining a
majority.
  As regards local representation, an important question is how to design
multi-member constituencies. It will be argued that using constituencies based
on natural demographic boundaries (such as local government areas) can combine
better local representation with stability over time and better
proportionality.
  STV is unsurprisingly best for voter empowerment and choice, as those are
parts of its basic idea.
  Broad conclusions are summarised within the Summary on page 1 of the paper.
  The paper makes use of recent public availability of large preferential
voting data sets for STV elections, making possible new analyses of how STV
functions in practice, and of voter behaviour, particularly examining how
voters' second preferences relate to their first preferences.
