From 374c45e5ef46eda860e9261079f737b5cf1687fd Mon Sep 17 00:00:00 2001 From: Jed Barber Date: Mon, 20 Feb 2017 10:54:44 +1100 Subject: Single transferable vote article added --- project/templates/stvcount.html | 275 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 275 insertions(+) create mode 100644 project/templates/stvcount.html (limited to 'project/templates/stvcount.html') diff --git a/project/templates/stvcount.html b/project/templates/stvcount.html new file mode 100644 index 0000000..a64f029 --- /dev/null +++ b/project/templates/stvcount.html @@ -0,0 +1,275 @@ + +{% extends "base.html" %} + + + +{% block title %}Single Transferable Vote Counter{% endblock %} + + + +{% block content %} + +

Single Transferable Vote Counter

+ +

To give an incredibly brief summary of Australia's political system, both the Federal Parliament and most of the State +Parliaments are bicameral. The lower houses are generally elected by Instant Runoff, while the upper +houses generally have half elections using Single Transferable Vote. There are exceptions and a whole +lot of differing details, but that's the overall pattern.

+ +

In 2016, however, the Federal Parliament underwent a Double Dissolution, causing the entirety of +both houses to go to an election. This had the outcome of 20 out of 76 seats going to third parties +in the upper house, a record number. Even more than the 18 there were prior. As the entire purpose of +a Double Dissolution is to break deadlocks in parliament, to have the outcome go in the +complete opposite direction probably caused some dismay from Malcolm Turnbull +and his Liberal/National government.

+ +

This raises the question: Would they have been better off had a normal election happened instead?

+ +

To calculate the likely outcome, the ballot preference data is needed. That's the easy part, as +the Australian Electoral Commission makes that available +here +in the 'Formal preferences' section. Then, a program is needed to execute the STV algorithm, which is +as follows:

+ +
    +
  1. Set the quota of votes required for a candidate to win.
    2. +
  2. Allocate the ballot papers according to first preference to each of the candidates for + initial vote totals.
    3. +
  3. Mark any candidate who has reached or exceeded the quota as elected.
    4. +
  4. If any elected candidate has more votes than the quota, transfer the excess to the other + candidates according to the next applicable preference.
    5. +
  5. If no further candidates meet the quota, the candidate with the fewest votes is eliminated + and their votes are transferred to the others according to next applicable preference.
    6. +
  6. Repeat steps 3-5 until all seats are filled.
    7. +
+ +

Seems simple enough, right? Except not really. There is a surprising amount of complexity in there, and most +of it is to do with how to transfer votes around. So, in addition, there are the specifics for the version +used for the Australian Senate:

+ + + +

My implementation (source here) also includes bulk exclusions using applied breakpoints in order to increase speed slightly and minimise +superfluous logging.

+ +

At this point I'm fairly sure my program provides an accurate count. However, my numbers still differ +slightly from the ones provided by the AEC's official distribution of preferences. Investigations into the +exact cause are ongoing.

+ +

Results

+ +

Calculations were done for each state using the formal preference data with vacancies set to 6 instead of 12, +and the results were added to the Senators elected in 2013 to find the probable outcome. The results for +ACT and NT were taken as-is, because the few Senators elected from the territories are not part of the half +election cadence anyway.

+ +

Computational resources required varied from approximately 50 seconds using 46MB of memory for Tasmania, to +nearly 30 minutes using 1452MB memory for NSW. The vast majority of that time was spent parsing preference data, +and the program is single threaded, so there is still room for improvement. All counts were run on a Core 2 Quad +Q9500.

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Probable non-DD results by state
NSWVICQLDSAWATAS
LiberalLiberalLiberal NationalLiberalLiberalLiberal
LaborLaborLaborLaborLaborLabor
LiberalNationalLiberal NationalXenophonLiberalLiberal
LaborLaborLaborLiberalLaborLabor
NationalGreenOne NationLaborGreenJacqui Lambie
GreenDerryn HinchLiberal NationalXenophonLiberalGreen
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Probable non-DD Senate composition
PartySeats WonContinuing SenatorsTotal SeatsDifference from Actual
Liberal/National Coalition171532+2
Australian Labor Party141024-2
Australian Greens448-1
Xenophon Group213Nil
Jacqui Lambie Network*112+1
Liberal Democratic Party011Nil
Family First Party011Nil
Palmer United Party*011+1
Glenn Lazarus Team*011+1
Australian Motoring Enthusiast Party011+1
One Nation101-3
Derryn Hinch's Justice Party101Nil
+ +

* These three parties were all part of the Palmer United Party at the 2013/2014 election, but split up mid term.

+ +

Surprisingly, these projected results still have 20 out of 76 seats held by third party candidates, despite +the half election putting them at a disadvantage. The number of third party groups the Liberal Nationals have to +negotiate with to pass legislation (assuming Labor and Greens attempt to block) equally remains unchanged.

+ +

The Greens manage to do slightly worse, even though their usual position of winning the 5th or 6th seat in most states +often allows them to obtain more representation than their primary vote would otherwise support. This can't even be +attributed to a bad 2013 result, as their primary vote both then and in 2016 was nearly identical.

+ +

One Nation's much reduced number of seats can be attributed to the inherent geographic bias that any system involving +electing multiple candidates across multiple independent divisions introduces. If like-minded voters are all in one +place, they receive representation, but when the same number of voters are spread out, they get nothing. When this effect +is intentionally exploited it's called gerrymandering, but here it's merely an artifact of electing Senators from each +state separately. One Nation's support is strongest in Queensland but is relatively diffuse. Any claims of Pauline +Hanson being one of the most powerful politicians in Australia are thus overblown.

+ +

The Xenophon Group, by contrast, has the vast majority of their support concentrated in South Australia. So the result +for them remains unchanged.

+ +

The most noteworthy outcomes for the question though, are that the Liberal/Nationals would have obtained more seats, +and Labor would have been in a more difficult position to block the passage of legislation. Meaning that yes, the +Liberal/National government would definitely have been better off with a normal election.

+ +

Nice job screwing over your own party, Malcolm.

+ +{% endblock %} + -- cgit