New trend graphs
I have been using a weighted monthly aggregation for some time now to peer behind the random lumpiness in week to week polling.
The regular Reuters poll trend suggested another methodology to get beyond the random lumpiness. In a manner similar to the Reuters poll trend, every time a poll is published (typically weekly) I take the simple average of the last poll from each pollster (Galaxy, Morgan, Newspoll and ACNielsen). I do not weight the average for differences in sample size. To that rolling average I then apply a 13 term Henderson moving average to smooth out the lumps and bumps. I chose a 13 period average because the results from the 5 period moving average were pretty lumpy.
The next set of graphs depict the underlying trends, as revealed by the 13 term Henderson moving average.
These charts tell pretty much the same story as the monthly aggregation. Rudd’s election as Leader reinvigorated Labor in the polls. Nonetheless, between March and July this year, the Coalition was beginning to claw back its position. In the last month, that clawback has reversed. The graphs also point to a decline in the Green and minor party vote since Rudd’s elevation; however, that decline has now plateaued.