Timothy McCarthy
Timothy McCarthy


A couple of weeks ago there were a few points made on Twitter about the extent to which Australia’s parliament reflects the diversity of Australia’s population. I thought it might be interesting to iterate on that question a bit, and do some poking around about the extent to which the Australian electorate is representative of its population. Further to that, I wonder whether our parliament is more reflective of the electorate than the population.

I’m hoping to do a couple of posts on this topic, but as with basically all blogs there’s every chance I’ll never revisit it after a post or two. In this post I’m going see how well the Australian electorate reflects our population with respect to age.

It’s worth disclaiming that I’m not particularly experienced at working with Australian census data and this kind of statistical analysis. Take it with a grain of salt.

Why should we care about the electorate?

There are obviously a number of ways to describe the role of voting in a democracy. Generally these are some variation on the theme of the “consent of the governed”. Equivalently, we could think of democracy as a system that seeks to improve outcomes by aligning the incentives of the government with the interests of the governed.

Regardless of whether we’re talking about “consent of the governed” or the “interests of the governed”, there is some notion of “the governed”. But in practise, all democracies (including Australia) have sizeable proportions of the population whose consent is never given, and whose interests are not expressed, because they do not or cannot vote. Where the demographics of voters and the population at large differ, we should expect different electoral outcomes, and thus different outcomes in government.

Australian democracy places a very strong emphasis on maximising the voting population as a portion of the whole. You could reasonably claim that this emphasis is stronger here than anywhere else in the world. This is down to a relatively broad franchise and compulsory voting for adult citizens. From Secret Ballot to Democracy Sausage: How Australia Got Compulsory Voting is an excellent read on how Australia ended up with this system.

Despite Australia’s broad franchise and compulsory voting, there are still a large number of Australian residents who do not vote, mostly because they cannot. International students and children are governed: they pay taxes, use government services and have to obey laws. And yet because children and non-citizens cannot vote, they neither give their consent to government, nor express their interests at the ballot box. There may be good reasons to disenfranchise these groups, but we should be clear-eyed that they are disenfranchised.

What is more, disenfranchising non-citizens and children clearly introduces large demographic differences between the electorate and the governed population. We would expect that this would lead to substantially different government versus the counterfactual of a truly universal franchise. My motivation for this and any subsequent blog posts is to explore just how the limits on Australia’s franchise lead to demographic differences between the population and the electorate.

Australia’s electorate


At the 2016 census, the Australian electorate constituted 63% of the population. By far the largest group of disenfranchised residents is Australian citizens under the age of 18. More than a fifth of the population are citizens who cannot vote because they are under the age of 18. It’s not hard to imagine that Australia’s government would look very different if this huge chunk of our population weren’t disenfranchised.

Comparing age distributions


If we ignore the massive distortion that comes from disenfranchising those under 18, the age distribution of the electorate tracks that of the population relatively closely. The electorate skews slightly younger, but it is a small difference. Note that parliament is not particularly representative of the population or electorate when it comes to age distribution, clustering much more strongly in the 40s and 50s.

Some notes on definitions

In this and subsequent posts, I’m going to analyse the Australian electorate thus:

The Australian electorate consists of census respondents who recorded themselves as citizens and were over 18.

That is, we’re analysing those people whose census answer indicates that they are eligible to vote in Australia. There are a couple of problems with this:

  • About 7% of census respondents (1.6 million people) did not state their Australian citizenship status.
  • Australian citizens overseas can register as electors in certain circumstances, but will not appear in the census.
  • Although enrolment is compulsory in Australia, not all eligible Australians enrol.

This is a substantial problem. At the 2016 election there were 15,676,659 people enrolled to vote, which is nearly 1 million more than the 14,668,091 whose 2016 census answer places them within our definition of the electorate. Despite this, the absence of census-level data about Australians on the electoral role means I’m going to carry on using the flawed census data for these analyses.

  1. This chart omits the 1,615,599 respondents that did not state their citizenship status (7% of overall respondents). 

  2. Parliamentarian age is calculated as at 2 July 2019, and uses the parliament as elected, ignoring resignations etc. MP birthdays are taken from here or from Wikipedia. I couldn’t find dates of birth for Tim Ayers or David Van, so they haven’t been included.