Systemic polling bias

Bryan · Wednesday 21 June 2006 · 4:32 am

For any given weekend since the last Federal election, it was not uncommon for ACNielsen and Newspoll to have estimates for the Greens that were statistically different. In plain English: at least one of the pollsters was wrong! This can be seen graphically.

Greens

This of course raises the question of systemic polling bias. To get a sense of the systemic differences between the pollsters, I have put together the following table. It gives the average poll results from the pollsters since the last election for each of the major party groups.

  Morgan ACNielsen Newspoll Divergence
Coalition 41.92 42.83 43.45 1.53
Labor 40.03 38.00 38.29 2.03
Green 8.43 9.89 6.42 3.47
Other/Minor 9.61 9.56 11.84 2.23
2PP Coalition (calculated using 2004 preference flows) 49.07 50.21 50.61 1.54
2PP Coalition (from polling) 48.40 48.83 - 0.43
2PP Coalition Divergence 0.67 1.38 -  

I am not convinced these results are necessarily meaningful. Morgan, for example, tended to report weekly on reduced sample sizes when it got anomalous results, which could skew its results in this analysis. For ACNielsen, I have excluded the results from June 2006, as its minor party primary vote prediction has not been made public yet.

Nonetheless, the results are indicative of a systemic polling bias problem - particularly with the Greens. I suspect this bias comes about from two sources. First, the way in which the pollsters develop their sample frame can bias the result. Second, the actual questions the pollsters ask and the sequence in which they are asked can also bias the prediction.

It is a significant issue, as these Green and minor party results feed into national two-party preferred estimate from each of the pollsters. From 2007, I expect Newspoll will report preference allocations according to the way in which people say they will vote, rather than use the preference flows from the previous election. Similarly, while Morgan reports both, I expect the focus to move to actual reported preference flows.

It is another useful reminder that interpreting polling results is as much an art, as it is a science. And it legitimises the practice of adjusting results from some polling organisations by a percentage point or two; although it is arguable which pollster is accurate and which is biased. For the record, I cannot quite come at the seven-point adjustment one of my regular commentators applies.

Note: in undertaking this analysis, I found an error in my earlier minor party charts in respect of the Morgan series. It has now been corrected. You may need to hit the refresh button on your browser to get the latest chart.

Compulsory voting

Bryan · Thursday 4 May 2006 · 7:34 am

The Australian Electoral Commission has released an information paper on compulsory voting. It is an interesting overview of the history of compulsory voting in Australia, and the arguments for and against compulsory voting.

This may become a live issue. After each federal election, the Joint Standing Committee on Electoral Matters (JSCEM) conducts an inquiry into the election and considers public submissions. The 1996 JSCEM recommended that compulsory voting should be repealed. The 2004 JSCEM recommended that a full and separate inquiry be held into voluntary and compulsory voting. While the Prime Minister has said that the abolition of compulsory voting will not occur before the next federal lection there are a number of members of the government, including influential ministers such as Senator Nick Minchin, in favour of voluntary voting.

A psephological feast

Bryan · Tuesday 28 February 2006 · 10:59 pm

The Parliamentary Library has released a whole bunch of papers. The psephologically inclined might want to get their fangs into:

Electoral Reform III

Bryan · Monday 10 October 2005 · 9:49 pm

The Joint Standing Committee on Electoral Matters (JSCEM) has today reported on its Inquiry into the Conduct of the 2004 Federal Election and Matters Related Thereto.

There are 56 recommendations, so space prevents me from listing them all. Some of the more sensible and contentious follow (I will let you decide which are which).

  • proof of identity for enrolment and re-enrolment
  • close of electoral rolls to be 8.00pm on the day of the writs
  • tightened registration and naming requirements for political parties, and the de-registration and re-registration of all parties not represented in Parliament to ensure they comply with the new rules
  • those wishing to cast a provisional vote to produce photographic identification
  • four-year terms for the House of Representatives
  • voluntary and compulsory voting be the subject of a future inquiry by the JSCEM
  • compulsory preferential voting above the line be introduced for Senate elections, while retaining the option of compulsory preferential voting below the line — the practice of allowing for the lodgement of Group Voting Tickets (only number one above the line) be abolished
  • compulsory preferential voting for the House of Representatives be retained
  • trial remote electronic voting for overseas Australian Defence Force and Australian Federal Police personnel, and for Australians living in the Antarctic

Fellow bloggers John Quiggin and William Bowe (aka The Poll Bludger) get quoted extensively on pages 275-283, and appear to have had a positive influence on the JSCEM — particularly given the horror stories circulating of wholesale reform of the Electoral Act as it applies to the internet. (Remember this article by Misha Schubert in the The Age on 16 March 2005).

Notwithstanding the acknowledged difficulties, the report discusses some changes to the regulation of the internet that could affect blog-based commentary on elections, and more particularly the political satire web sites.

Recommendation 44

12.29 The Committee recommends that the AEC review section 328 of the Commonwealth Electoral Act to devise authorisation requirements for electoral advertisements, as distinct from general commentary, on the internet.

12.30 In drafting these amendments, the AEC should ensure that the definition of published electoral matter specifies that the authorisation requirements are also to apply to material republished on the internet. In this instance, the AEC should determine a cut off point for disclosure of authorisations, such as whether disclosure of the original sponsor, as well as of the immediate re-publisher of the material, will be sufficient.

12.31 The Committee also considers there may be merit in a broader review of authorisation requirements within s328 of the Electoral Act, to ensure greater transparency of financial disclosures or party political affiliations.

12.32 The AEC may consider, for example, the feasibility of setting requirements for registration of the names of web domains commenting on political matters. This could also include consideration of requirements for identification of political party sponsorship on any websites making political commentary

Recommendation 45

12.33 The Committee recommends that the AEC review section 328 of the Commonwealth Electoral Act to enhance the accountability and transparency of the electoral process.

William Bowe should be particularly pleased with the recommendation to remove section 350 from the Electoral Act (recommendation 46). That section provides criminal actions and penalties for defamation against electoral candidates. A candidate dissatisfied with William’s (most excellent) electorate guide initiated a private prosecution against William for an alleged breach of section 350.

Electoral Reform II

Bryan · Wednesday 5 October 2005 · 7:21 am

What an interesting 24 hours. According to Michelle Grattan and Misha Schubert (also here), no sooner than voluntary voting had been proposed, the Prime Minister ruled it out.

“We are not considering it, we will not be proposing it for the next election,”

A clarification or two later, it appears that advocates for voluntary voting within the Liberal Party have the license to continue arguing their case within the party room. If they get lucky (which seems unlikely in the face of moderate Liberal and National opposition) it could become party policy after the next election.

From the SMH, the ABC, the Oz and the Courier Mailthe we learn that while voluntary voting is out, other reforms look like going ahead,

  • optional full preferential, above-the-line voting for the Senate and (implicitly) primary vote thresholds before candidates or parties can be elected
  • all prisoners serving a full-time custodial sentence would be struck off the electoral roll (currently prisoners serving terms under three years are not struck off)
  • stronger identity requirements for people enrolling to vote and casting their ballot on polling day
  • the electoral roll would close the moment an election is called (not seven days later as it does currently)
  • the campaign finance threshold for anonymous donations to political parties would be raised from $1500 to $10,000
  • the donation amount that could be claimed as a tax deduction would be increased
  • financial disclosure rules for unions and non-government groups would be tightened
  • a referendum on flexible four year parliamentary terms would be explored further
  • electronic voting would be tested

Abetz’s opinion piece on Senate voting was in yesterday’s Australian.

Update: The full text of Abetz’s speech — Electoral reform: making our democracy airer for all — is now available.