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diff --git a/project/complexity.yml b/project/complexity.yml index c25e9fa..07417a2 100644 --- a/project/complexity.yml +++ b/project/complexity.yml @@ -13,4 +13,5 @@ unexpanded_templates: - "grasp.html" - "thue2a.html" - "adapad.html" + - "stvcount.html" diff --git a/project/templates/index.html b/project/templates/index.html index b8db7fe..de16dbf 100644 --- a/project/templates/index.html +++ b/project/templates/index.html @@ -5,6 +5,7 @@ {% block content %} <ul class="index"> + <li><a href="/stvcount.html">Single Transferable Vote Counter</a></li> <li><a href="/adapad.html">Adapad</a></li> <li><a href="/grasp.html">Grasp Interpreter</a></li> <li><a href="/thue2a.html">Thue Version 2a</a></li> 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 %} + +<h4>Single Transferable Vote Counter</h4> + +<p>To give an incredibly brief summary of <a href="https://en.wikipedia.org/wiki/Parliament_of_Australia" +target="_blank">Australia's political system</a>, 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.</p> + +<p>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 +<a href="http://www.abc.net.au/news/2016-07-03/crabb-election-2016-is-lose-lose-for-malcolm-turnbull/7565840" +target="_blank">complete opposite direction</a> probably caused some dismay from Malcolm Turnbull +and his Liberal/National government.</p> + +<p>This raises the question: Would they have been better off had a normal election happened instead?</p> + +<p>To calculate the likely outcome, the ballot preference data is needed. That's the easy part, as +the Australian Electoral Commission makes that available +<a href="http://results.aec.gov.au/20499/Website/SenateDownloadsMenu-20499-Csv.htm" target="_blank">here</a> +in the 'Formal preferences' section. Then, a program is needed to execute the STV algorithm, which is +as follows:</p> + +<ol> + <li>Set the quota of votes required for a candidate to win.</li> + <li>Allocate the ballot papers according to first preference to each of the candidates for + initial vote totals.</li> + <li>Mark any candidate who has reached or exceeded the quota as elected.</li> + <li>If any elected candidate has more votes than the quota, transfer the excess to the other + candidates according to the next applicable preference.</li> + <li>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.</li> + <li>Repeat steps 3-5 until all seats are filled.</li> +</ol> + +<p>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:</p> + +<ul> + <li>Voters are given the option of voting either "above the line" or "below the line". The latter is + standard STV. The former used to be a group voting ticket, but for 2016 and later it is treated as + a shorthand way of voting, as per instructions + <a href="http://www.aec.gov.au/Voting/How_to_vote/Voting_Senate.htm" target="_blank">here</a>.</li> + <li>There are <a href="http://www.aec.gov.au/Elections/candidates/files/ballot-paper-formality-guidelines.pdf" + target="_blank">specific guidelines</a> on what constitutes a correctly filled out ballot. This is + important for parsing the formal preference data.</li> + <li>The <a href="https://en.wikipedia.org/wiki/Droop_quota" target="_blank">Droop quota</a> is used.</li> + <li>All votes are transferred from elected candidates at a fraction of their value, as per the + <a href="https://en.wikipedia.org/wiki/Counting_single_transferable_votes#Gregory" target="_blank"> + Gregory Method</a>. This can result in fractions with surprisingly large numerators and denominators. + This also results in occasional discarding of fractional votes during transfers.</li> + <li>Should the next applicable preference of a ballot be a candidate who has already been elected, that + preference is ignored and the ballot is transferred to the next preference.</li> + <li>If the number of remaining candidates is equal to one more than the number of remaining vacancies, + the candidates with the highest vote totals at that point are considered elected.</li> +</ul> + +<p>My implementation (source <a href="http://jedbarber.id.au/cgit/cgit.cgi/stv-count.git/" +target="_blank">here</a>) also includes <a href="https://en.wikipedia.org/wiki/Counting_single_transferable_votes#Bulk_exclusions" +target="_blank">bulk exclusions</a> using applied breakpoints in order to increase speed slightly and minimise +superfluous logging.</p> + +<p>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.</p> + +<h4>Results</h4> + +<p>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.</p> + +<p>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.</p> + +<table> + <caption>Probable non-DD results by state</caption> + <tr> + <th>NSW</th> + <th>VIC</th> + <th>QLD</th> + <th>SA</th> + <th>WA</th> + <th>TAS</th> + </tr> + <tr> + <td>Liberal</td> + <td>Liberal</td> + <td>Liberal National</td> + <td>Liberal</td> + <td>Liberal</td> + <td>Liberal</td> + </tr> + <tr> + <td>Labor</td> + <td>Labor</td> + <td>Labor</td> + <td>Labor</td> + <td>Labor</td> + <td>Labor</td> + </tr> + <tr> + <td>Liberal</td> + <td>National</td> + <td>Liberal National</td> + <td>Xenophon</td> + <td>Liberal</td> + <td>Liberal</td> + </tr> + <tr> + <td>Labor</td> + <td>Labor</td> + <td>Labor</td> + <td>Liberal</td> + <td>Labor</td> + <td>Labor</td> + </tr> + <tr> + <td>National</td> + <td>Green</td> + <td>One Nation</td> + <td>Labor</td> + <td>Green</td> + <td>Jacqui Lambie</td> + </tr> + <tr> + <td>Green</td> + <td>Derryn Hinch</td> + <td>Liberal National</td> + <td>Xenophon</td> + <td>Liberal</td> + <td>Green</td> + </tr> +</table> + +<table> + <caption>Probable non-DD Senate composition</caption> + <tr> + <th>Party</th> + <th>Seats Won</th> + <th>Continuing Senators</th> + <th>Total Seats</th> + <th>Difference from Actual</th> + </tr> + <tr> + <td>Liberal/National Coalition</td> + <td>17</td> + <td>15</td> + <td>32</td> + <td>+2</td> + </tr> + <tr> + <td>Australian Labor Party</td> + <td>14</td> + <td>10</td> + <td>24</td> + <td>-2</td> + </tr> + <tr> + <td>Australian Greens</td> + <td>4</td> + <td>4</td> + <td>8</td> + <td>-1</td> + </tr> + <tr> + <td>Xenophon Group</td> + <td>2</td> + <td>1</td> + <td>3</td> + <td>Nil</td> + </tr> + <tr> + <td>Jacqui Lambie Network*</td> + <td>1</td> + <td>1</td> + <td>2</td> + <td>+1</td> + </tr> + <tr> + <td>Liberal Democratic Party</td> + <td>0</td> + <td>1</td> + <td>1</td> + <td>Nil</td> + </tr> + <tr> + <td>Family First Party</td> + <td>0</td> + <td>1</td> + <td>1</td> + <td>Nil</td> + </tr> + <tr> + <td>Palmer United Party*</td> + <td>0</td> + <td>1</td> + <td>1</td> + <td>+1</td> + </tr> + <tr> + <td>Glenn Lazarus Team*</td> + <td>0</td> + <td>1</td> + <td>1</td> + <td>+1</td> + </tr> + <tr> + <td>Australian Motoring Enthusiast Party</td> + <td>0</td> + <td>1</td> + <td>1</td> + <td>+1</td> + </tr> + <tr> + <td>One Nation</td> + <td>1</td> + <td>0</td> + <td>1</td> + <td>-3</td> + </tr> + <tr> + <td>Derryn Hinch's Justice Party</td> + <td>1</td> + <td>0</td> + <td>1</td> + <td>Nil</td> + </tr> +</table> + +<p>* These three parties were all part of the Palmer United Party at the 2013/2014 election, but split up mid term.</p> + +<p>Surprisingly, these projected results <em>still</em> 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.</p> + +<p>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.</p> + +<p>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 <a href="http://junkee.com/malcolm-turnbull-will-probably-need-pauline-hansons-support-to-pass-any-laws/82138" +target="_blank">one of the most powerful politicians in Australia</a> are thus overblown.</p> + +<p>The Xenophon Group, by contrast, has the vast majority of their support concentrated in South Australia. So the result +for them remains unchanged.</p> + +<p>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.</p> + +<p>Nice job screwing over your own party, Malcolm.</p> + +{% endblock %} + |