Advance Summary
1. One of the most important factors in state election outcomes is the influence of whether the governing party at state level is in Government or Opposition federally. To be the same party as the federal Government is a disadvantage.
2. Another important factor is the age of the state government, with governments tending to do worse the longer they have been in office.
3. In the last six years, all same-party state governments that have faced elections have lost seats in significant numbers.
4. In the meantime, two of the three opposite-party governments gained seats (though one very old opposite-party government was defeated, but with a 2PP swing to it.)
4. It might seem logical that if the federal government at one state election was the same as at the previous election for that state, then this factor would not generate further swings against an incumbent state government of the same party, or further protection for one of the opposite party.
5. However, the evidence suggests otherwise. It appears that more voters continue turning against state governments that are of the same party as the federal government, over successive elections, even when the same federal government had been in office at the state election before.