NATIONAL POLL AVERAGE & SEAT PROJECTION
NATIONAL POLL AVERAGE CHART
Last Update: 21 January 2013
Update trigger: New Essential Research Poll
TPP change from previous update: Coalition TPP down 0.1% (prev update 14 January 2013)
Seat Projection Central Forecast change from previous update: Coalition loses 1 seat, Labor gains 1 seat (prev update 14 January 2013)
How is the national poll average calculated?
- Only the last poll for each pollster is used in the average .
- Face to face polls are not to be included in the average.
- Polls will be kept in the average until the 15th day after the last day the sample was taken. The 15th day exclusion will be suspended in December and January.
- Each poll is weighted by number of respondents in the poll. A poll of 1500 respondents has 3 times more weight in the average than a poll of 500 respondents.
- If any single poll primary vote figures do not add up to 100% the figures will be scaled up to 100%.
- The primary vote average is used to project a two-party preferred vote based on the preference flow at the last election, namely; Greens: 78.84% to ALP, Others 60.96% to the Coalition.
How are the state averages calculated?
- We take every state by state break down published in an Australian opinion poll during the past three months. Currently, such breakdowns are only published by AC Nielsen in the Fairfax press and Newspoll in The Australian.
- For each state in each poll, the deviation from the national result is calculated. For example, if in an AC Nielsen poll, if the national Labor primary vote is 27% and in NSW the Labor primary vote is 26%. The NSW deviation in the Labor primary vote is -1%.
- All such deviations for each mainland state are included in an average weighted by sample size. This gives us an average deviation for each state.
- The average deviations for each state are added or subtracted to the current national poll average to create state primary vote figures.
- State primary votes for the Greens and others are distributed as per how they flowed as preferences in that state at the last election to create state TPP figures.
How is the seat projection calculated ?
The seat projection method is described here.