[EM] Gerrymandering and PR

Adam Tarr atarr at ecn.purdue.edu
Tue Mar 19 16:17:57 PST 2002

>>If the
>>election is done using open party list, then voting is very simple no
>>matter how many candidates there are.
>My concern is not the method.  My concern is that electoral districts be a
>reasonable size so that campaign costs aren't unmanageable.  Also, I worry
>that if each party's slate is too large the individual candidates will
>receive less scrutiny.

These are valid concerns, which, along with practical voting and counting 
concerns, argue against very large districts.  On the other hand, if you have 
small districts you don't get real proportionality.  In my opinion, you have to 
have at least 5 or 6 seats in a district to get acceptably proportional results. 
 The more fractionalized the electorate is, the more seats per district you 

>If PAV were used for large multi-
>member legislative districts, and some of those districts crossed county
>lines (a virtual guarantee in CA, given the distribution of population)
>vote-counting with PAV would be logistically more tricky (although not
>totally unwieldy).

As Forest pointed out (correcting me), PAV ballots can be represented in data 
structures of size C(m,n), where m is the number of candidates and n is the 
number of seats.  Since these data structures are summable, having many 
different ballot-counting locations is not a problem.

>I dislike Adam's idea of linking the elections of the two houses of the
>legislature.  (concerns follow)

Well, it's not really my idea; I think that the German legislature works this 
way.  But I agree that it is a hack.  But if you don't do this then you don't 
really have proportional representation.  The bottom line is that single-member 
districts lead toward Gerrymandering and lead away from proportional 

Ideally, I think that there should be no single-member districts for legislative 
appointments.  The disadvantages seem to outweigh the advantages.  But in 
certain cases (US Senate for example) there doesn't seem to be another option.

>As for party-list, I don't understand the "above the line" and "below the
>line" distinctions.  My vague understanding is that when all seats are
>apportioned according to how many votes a party got (be it state-wide,
>district-wide, whatever) in an "open list" system you vote for a party and
>also one or more candidates in that party.  Seats go to the most popular
>candidates of the party.  In a closed system, it's been decided in advance
>that if the party only gets one seat, Bob gets it, and if they get two
>seats Jane gets one, and the third goes to Fred, etc.

This is correct, in the case of open party list and closed party list.  In 
Australia, they have "above the line" and "below the line" voting, but both are 
actually STV.  If you vote "above the line" you just check off a party, which 
amounts to voting for all that party's candidates in the order which they are 
listed.  If you vote "below the line" you vote for specific candidates and you 
set the order, one through whatever.

You could think of "above the line" as closed list and "below the line" as open 
list, but that's not exactly true since it's actually STV either way.


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