Category Archives: Dunkley By-Election

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Dunkley Election - VIC Demographic Analysis, Profiling & Mapping

Dunkley By-Election

Category:By-Elections,Dunkley By-Election

I’ve written a profile of the by-election on Saturday in Dunkley for the Australian Financial Review, putting it in the context of our 2022 National Election Personal Vote Profiles and our profiles in Aston and Fadden.   

See AFR story here: 🔗

The three individual seat profiles use ADS modelling of personal votes to  estimate the impact of the retirement or death of an MP with a large personal vote on the subsequent by-election result.

The personal vote for sitting members tends to be higher for provincial city or rural seats, as they are demographically more stable and voters are more likely to live and work in the same seat. These voters are easier for sitting members to locate at work or home and they tend to live in the same seat for a few elections and so are more likely to have a personal knowledge of their MP either socially through family sporting events, or officially, if they seek assistance with a federal Government matter, to do with transfer payments for example. The personal vote therefore builds up over time for these MPs.

To illustrate this point ADS modelling of the 2022 General Election showed a personal vote of more than ten percent for three female ALP MPs in Richmond, (Justine Elliot), Eden-Monaro (Kristy McBain) and Corangamite (Libby Coker) and without this personal vote, Labor would not have won their seats in 2022. So the personal vote is crucial when it comes to winning marginal seats.

Because the average personal vote of sitting Government members is typically about three to five percent, this figure is often confused by commentators with an average by-election swing of three to five percent against the Government if the Government MP leaves office unexpectedly in a by-election.

Unfortunately this simplistic use of swings comes unstuck when an Opposition MP with a big personal vote, such as we saw in Aston, retires and the resultant re-allocation of his personal vote back to the Labor tally produces a swing towards the Government. Oops.

Knowing this personal figure for the seat as a whole, we then profile the range of by-election swings for individual seats across booth catchments and profile these against key demographics across the same booth catchments.

This is a tricky exercise, especially with increasing numbers of pre-poll votes in a limited number of booths and a small number of matched pairs of booths. So caution is exercised.

But when we are looking at a strong inferential relationship significant to more than 99 percent confidence levels between votes and big demographics like Female Professionals and Male Construction workers in Dunkley, it is possible to make some comments, especially when it is consistent with longer term trends at general elections and demographic break downs of regular aggregated polling data.

Our Senior Demographic Mapper Dr Jeanine McMullan used our polling booth catchments to show some of the spatial links between Dunkley vote swings and Dunkley demographics at the by-election. Using the various layers, the reader can form their own impressions from the relationship between the swing to Labor and Professional Women and between the swing to the Liberals and Men working in Construction.

The link for the map is here: