A not-so-actuarial look at the marriage equality ballot

David Kwak from Actuarial Edge, wanted to take a closer look at the demographic data of the marriage equality ballot carried out earlier this year. He finds some interesting facts regarding participation rates, proportion of yes votes and difference in votes across States and Territories. 

On the 15th of November 2017, the result of one of the most polarizing ballots was revealed; Australia had voted for Marriage Equality. Of the 158 Federal Electorate Divisions (FEDs), 141 (89%) had ‘Yes’ as their majority vote. Not satisfied with just knowing the result of the vote, we decided to have a brief look into the demographics underpinning this monumental ballot, using data available from the Australian Bureau of Statistics (ABS)[1].


The ABS offers data on participating voters by FED, age and gender. Consistently across the different stats, women were more interested in the vote than men were, beating them in participation across all age groups.

25-29 year olds had the lowest of participation rates, while those aged between 70 and 74 had the highest participation rate.


The spike in participation rates for 18-19 year olds is reminiscent of the ‘accident hump’ in mortality curves – though I’m sure the voters in that age group did not vote by accident!

There was little difference across states, with the exception of the Northern Territory, where 58.4% of the eligible voters participated in the ballot.


At the end of the day, the most important statistic is the proportion of votes for and against marriage equality.

A quick calculation of average voter age for each FED suggests that the older the voter, the less likely they were to vote yes. The voting outcome range is greatest for FEDs with average ages between 46 and 50. This trend may be indicative of the old traditional values, where same-sex relationships were frowned upon.

When we rank the FEDs by the proportion of voters who voted yes, we see that the following FEDs are the most and least supportive of Marriage Equality:

FEDs in New South Wales were polarized in their support for or against marriage equality. Whilst 3 FEDs in NSW were in the top 5 FEDs with the highest yes votes, the bottom 5 FEDs with the lowest yes votes were also all from NSW.

So what makes these FEDs different from each other? A quick demographic check[2] revealed the following statistics:

The electorates with the least support for marriage equality tended to have:

  • a significantly higher proportion of people describing themselves as religious;
  • more couples with children;
  • lower average income levels; and
  • lower levels of attained education.

While many have argued the necessity of politicians taking the marriage equality vote to the public, it has certainly provided some interesting statistics; it would be very exciting to see how the distribution of married couples evolves over time due to this monumental ballot.

[1] Source: Australian Bureau of Statistics, released 15 November 2017, http://www.abs.gov.au/AUSSTATS/abs@.nsf/Lookup/1800.0Main+Features12017, accessed 23 November 2017

[2] Source: Sydney Morning Herald, http://www.smh.com.au/federal-politics/electorate-map/, accessed 23 November 2017

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