Proportional Representation Methods

[DEMOREP1 at aol.com]

New folks on the EM list should be aware that pending direct democracy (where
all of the voters directly enact the laws) there are various exact and inexact
proportional representation methods for electing legislative bodies (in
addition to the various single winner methods for electing executive and
judicial officers that is taking up most of the time and space on the EM
list).

Areas-
      At large- electing some or all of the legislators
      Districts- electing 1 (single member districts) or more (multi-member
districts) of the legislators in each district

Exact p.r. Methods
  
          Direct Proxy-- Each legislator has a voting power equal to the votes
he/she receives directly from the voters using single transferable votes
(STV).

          Indirect Proxy-- Each legislator has a voting power equal to the
votes he/she receives indirectly from other losing candidates using STV (i.e.
a voter votes for only 1 candidate, losing candidates transfer their votes to
other candidates).

A Condorcet method (with N legislators to be elected in the specific area) is
used.   A less accurate but much quicker method would use instant runoff
(IRO).

Inexact p.r. methods-- Each inexact method by definition does NOT have a
legislator have a voting power equal to the votes that he/she receives in
being elected.  Namely, each legislator has a voting power of 1 in the
legislative body.

     Lists- a group of voters (partisan or independents) puts a list of
candidates on the ballots.
       Closed lists- A vote for the list is for the order of the candidates on
the list
       Open lists- A voter can choose somewhat among the candidates on the
lists.   Variations- ordered list with optional single vote, ordered list with
optional multiple vote, unordered list with optional multiple vote, unordered
list with required single vote.

Additional member systems- part of the legislative body (generally one half)
is elected from single member districts. Additional legislators are elected
based on the votes for the various lists.
     Single ballot compensatory- used in single member districts.
     Double ballot compensatory - used in multi-member districts (also called
MMP).
     Double ballot noncompensatory- adds seats based only on the areawide
votes.

Formulas- The various inexact methods use a math formula to apportion seats
based on the votes.  Some of the formulas- Hare, Droop, Largest remainder,
d'Hondt, Sainte-Lague, Method of equal proportions.

Semi-proportional methods-
     Cumulative vote, Limited vote, Single nontransferable vote.

For details- See the book Real Choices, New Voices by Douglas J. Amy (1993)
especially Appendices A and B.
See the pamphlet- Proportional Representation by Douglas J. Amy (1997)
(especially Appendices 1 and 2) (a short version of the book)

For a major p.r. bibiography see
http://www. mtholyoke.edu/acad/polit/damy/prlib.htm