More on Informals and other electoral goodies.
Posted by Possum Comitatus on January 26, 2008
One of the problems we had with the informal voting model last time that caused some consternation was the use of non-linear variables, particularly using the squared value of the proportion of the electorate that spoke English poorly or not all – the NES variable.
The reason the square of the value was used was that it explained the data generation process better than its simple value.
The big problem wasn’t only the four electorates with the highest NES proportion, but 15-20 seats that had relatively low informal votes considering their NES level.
After ferreting around the census data, if we control for the proportion of the electorate whose highest level of schooling is year 10 or less (we’ll call this variable EDUCY10), what appears to be the slight non-linearity in the relationship between the informal vote and NES disappears.
Interestingly there is a slight correlation between NES and EDUCY10, in that the higher the proportion of the electorate with a Year 10 Education or less, the proportion of people that speak English poorly or not at all tends to be (slightly) lower.
This correlation between independent variables can create a problem called collinearity, however after testing NES against the EDUCY10, the Tolerance was 0.835 and the Variance Inflation Factor was only 1.12 meaning that collinearity simply isn’t an issue here.
So after partially controlling for education and removing what looked to be a non—linear relationship between NES and the informal vote level, our new equation becomes:
We can now explain over two thirds of the variation in the informal vote, by electorate, simply as it being a function of :
– The proportion of the electorate that speaks English poorly or not at all.
– The square of the number of candidates standing in an electorate
– The proportion of an electorate that has a year 10 education or less
– Whether optional preferential voting operates at the state level for that electorate.
Using the square of the number of candidates rather than just the simple number of candidates that stood in each electorate explains the data generation process (i.e. the election) slightly better. What this means is that as the number of candidates increases on the ballot paper, the informal vote increases in a slightly disproportional way. Not much, but enough to warrant paying attention – it’s essentially a compounding informal effect for candidate numbers.
Moving right along to some more interesting results of the election that aren’t as niche as informal voting, lets have a look at the primary vote of Family First plotted against the number of candidates that stood in each electorate, and lets run a simple regression with the two:
As the number of candidates increases, generally the Family First Vote decreases. That might sound like an obvious consequence that should happen to all parties – but it actually doesn’t (except for the ALP which we’ll get to a little later on)
At first I thought this might have had a bit to do with geography, with FFP picking up some of the bible belt vote in rural electorates that have few candidates – so after controlling for population density and running the equation again we get:
Which doesn’t make a great deal of difference to the size of the ‘candidate number’ effect on the FFP vote. Putting it another way, it smells like some evidence to suggest that a lot of people only vote for Family First because they happen to have a candidate standing, when ideally a lot of those voters would prefer to vote for some other minor party or independent if given the chance.
FFP seems to have a large soft vote.
Next up is something to chew over for the ALP staffers and pollies that are reading.
If we test the size of the two party preferred swing to the ALP in each electorate against the size of the Green vote (telling us if there is any statistical relationship between an increasing Greens vote and an increasing ALP swing) we get:
Yikes! This is telling us that far from a high Greens vote delivering a large ALP swing, the opposite happens where the higher the Greens primary vote, the lower the two party preferred swing to the ALP – a major implication in terms of the power that each party could wield in preference negotiations.
However, if we do this again but control for the number of candidates in each electorate as well, we get:
[I somehow managed to run a regression on a sample of the electorate results rather than the full electorate results when I controlled for CANDIDATES- yes, yes “WTF?” was what I was asking myself too. Candidate numbers have no bearing on this result once we test all 150 electorates rather than just the 16 I somehow managed. .]
That’s a juicy figure there – for every 3% chunk of the vote that the Greens received in an electorate, the two party preferred swing to the ALP reduced by just over 1%. Food for thought for both Comrades and Greens alike.
Finally for today, we know there is a relationship between the ALP primary vote and the proportion of the electorate that speak English poorly or not at all:
We also know that there is a relationship between NES and the level of the informal vote because we measured it earlier, so it’s not a great leap to reach the conclusion that a reduction in the informal vote would more than likely increase the ALP primary vote in many seats. If we model the relationship between the ALP primary vote and the informal vote that best fits the data (a simple quadratic regression) we end up with a modelled Informal vs ALP Primary vote relationship like this (which explains about 30% of the variation in the informal vote):
Some of that informal relationship, particularly in seats with an ALP primary close to 50% and beyond, would be easily explained by the nonchalant way HTV cards are often distributed in ultra-safe ALP seats (which also tend to have high NES populations… ta da!). But between the 40-47% ALP primary vote level, seats where HTV cards are definitely handed out in ways that certainly aren’t so nonchalant, if the informal vote can be reduced in those seats, those marginal seats, that informal reduction looks like it would flow more to the ALP than the Coalition by a fair margin. A 1.5% reduction in the informal vote across the board would have handed the ALP at least an extra 3 or 4 seats, possibly more.
So what’s the bet that the AEC will find themselves with new funding for voter education, specifically for targeting NES demographics and people whose maximum education level is year 10 or less (which, when controlling for population density, actually tended to vote for the ALP) ?
Especially since there’s seats in it for the new government.
For anyone interested, the Parliamentary Library has just released a Research Paper on Electoral redistributions during the 42nd Parliament (that’s this one), which gives us a good background on a lot of what’s likely going to happen with the all important redistribution coming up before the next election.