Advantages of Mixed-Member Proportional Representation (MMP) over an upper house

Advantages of Mixed-Member Proportional Representation (MMP) over other more well-known options like Hare-Clarke as in Tasmania or the ACT, or a Single Transferable Vote Upper house like the most Australian states or the Australian Senate:-

1. The big one is of course Proportionality. With MMP the number of seats each party gets in parliament very closely reflects the percent of the vote they got from the electorate, depending on the number of seats it could be basically a seat per percent of vote. In Tasmania the threshold for a party to get a seat is 16.5%, the ACT either 14.2% or 16.5% depending on the seat, and in the Senate 14.2%.
2. The second main advantage of MMP is that is addresses issues in the house that forms government, in contrast to adding an upper house that leaves the more powerful lower house untouched. A unicameral system allows for progressive changes to be passed, whereas introduction of an upper house only potentially allows for regressive changes to be blocked.
3. MMP addresses government being formed with less than majority support of the electorate, instead of 100% of the power going to the party with about a third of the support of the electorate. An upper house doesn’t effect the formation of government.
4. MMP almost certainly requires coalitions of more than one party to form government. This is more representative, but also makes parliament more relevant as decisions not made within one party. With an upper house this level of co-operation is not required and not on equal terms as the generally one party government always controls the lower house so continues to set the agenda.
5. MMP retains local electorate parliamentarians which many people think is important to the functioning of a representative democracy.
6. MMP addresses the neglect of safe seats, with elections focused on the lower house currently only about swinging voters in swinging seats, because every vote counts towards determining how many seats a party gets in parliament. The high thresholds in upper houses still translate to relatively safe seats and the election will remain focused on the lower house. There is just one election rather than two with everyone only focusing on the first one and ignoring the upper house.
7. MMP leading to minority government forces political parties to try to work together issue by issue rather than being in a constant adversarial political theatre. Parliament at present is largely a complete waste of time being a rubber stamp for the one party government. With an upper house the focus is still on the lower house where government is formed, and again the one party government sets the agenda and a majority in the upper house can’t pass anything without government support.
8. In MMP there is a greater incentive for parties to engage with those currently disengaged from politics to increase turnout to get the largest proportion of votes possible. Every vote counts towards how many seats the party ends up with, including those not currently voting, or voting informal.
9. MMP ensures that there will be a viable Opposition, unlike in Queensland after the 2012 election.
10. MMP with its lower bar for entry for political parties, means greater representativeness, and allowing for entry of new parties into parliament allowing rejuvenation of politics.
11. Due to its greater proportionality MMP is largely immune to disproportionate changes in results form small changes in votes that upper houses are. A small decrease in vote saw the ALP’s representation halved in the Senate in Queensland last election.
12. In MMP there is an advantage to parties being able to have an actual presence on the ground to campaign across the state, so works against public relations fronts like Clive Palmer’s party United Australia, but also even the ALP and LNP would have an incentive to really engage with their memberships and thus improve internal democracy in political parties. Upper houses tend to mean parties still neglect large areas of the electorate because the next threshold is out of reach.
13. MMP facilitates the break up of old parties kept together despite internal differences due to the demands of the electoral system. This is important to address institutional problems inherent in long established parties, and for the rejuvenation of politics.
14. MMP can be introduced without any increase in the number of parliamentarians which is an issue for many people (though it shouldn’t be as we have too few representatives per voter). While an upper house could be introduced without any increase in parliamentarians that would likely mean very high thresholds for entry making it less proportional and possibly dominated by the ALP or LNP.
15. In MMP the voting system from the perspective of the voter could in theory stay the same with the one vote variation, that is the ballot and how voters vote could be identical, so the transition would be very smooth. Even with the more common two vote system the change would be relatively straight forward in contrast to an upper house vote which requires `tablecloth’ ballot papers as we see with the Senate.
16. It is easier to introduce other affirmative action targets for parliament via the list MPs.
17. MMP doesn’t duplicate parliamentary processes as an upper house would.
18. In a one vote variation of MMP where the list is automatically generated the power of behind the scenes party hacks can be limited and parliamentarians given an incentive to better represent their electorates.