One of the more common criticisms of MMP relates to the status of list MPs. The biggest gripe occurs when electorate MPs lose their electorate seats but stay in Parliament as list MPs. The party list is popularly seen as a kind of Parliamentary back door.

The criticism is weakened by the lack an argument about who else should be list MPs. After all, both list MPs and electorate MPs are pre-selected by their parties, and it is in the parties' interest to choose the best possible people for electorates and for list places.

A general election is a set of contests. Each electorate is a contest about local representation. Being rejected in an electorate is not the same as being rejected by the country as a whole.

Electorates use FPP voting, which makes them to some extent a lottery. Electorate MPs can lose while increasing their share of the local vote. Winston Peters won Tauranga in 1999 with a much smaller percentage of the vote than he got as the defeated candidate in 2005. Defeated electorate MPs often score a bigger percentage of the vote than undefeated colleagues in other electorates. (A classic example was actually the Auckland Mayoral elections in 2004. Auckland City mayor John Banks was dumped in a 2-way contest, while Manukau City mayor Barry Curtis held on in a 3-way contest with significantly less votes than Banks received.)

Under MMP, it is no sure thing to get in on the list if defeated in an electorate. Indeed, the major parties did not get many list MPs at all in 2002. One of the big problems with FPP is the magnified swings; a 5% inter-party swing on votes might be a 15% swing in electorates. The MMP party list is a compensating mechanism that enables, among other things, cabinet ministers to represent marginal electorates. Indeed it should be understood as normal for someone like Dianne Yates (Hamilton East) to oscillate between being a list and an electorate MP.

If electorate candidates could not also be list candidates, then the triennial turnover of MPs would be unacceptably high. The average experience of any particular gaggle of MPs would be low, and quality candidates would be reluctant to disrupt professional careers to become MPs.

One reason for an electorate MP to be defeated is that s/he has such great responsibilities as a Cabinet Minister or Party Leader that s/he has little time to be an effective local MP. Choosing someone else as a local MP can by no means be taken as a vote against the defeated incumbent's wider role. Take for example Richard Prebble and Winston Peters, both party leaders who were defeated as local MPs because their wider roles precluded them from being principally advocates for their electorates.

Certainly under FPP there were times when a nationally unpopular MP was dumped by the local electorate on behalf of the whole country (Max Bradford in 1999?). But there were more times when a nationally unpopular MP was not dumped, because s/he was in a "safe seat". George Hawkins might fit that category this time.

FPP was much better at sheltering incompetent MPs than MMP. Today, the parties are quick to place the non-performers down their party lists.

An election is a contest. Critics of a system that gives MPs who lose a local contest a second chance in the nationwide contest must spell out their preferred alternative. The best way we can illustrate this is to note the names of the Labour MPs who, on election night, lost their electorate seats but returned as list MPs, and then to note who would have been in Parliament in their places had those defeated electorate MPs not been on their party lists.

The defeated Labour electorate MPs are: Rick Barker; Jim Sutton; Dianne Yates; Russell Fairbrother; Ann Hartley; David Parker; Jill Pettis; Dover Samuels; Mita Ririnui. The top nine unsuccessful Labour Party list candidates are: Charles Chauvel (a great University Challenge performer in 1985), Lesley Soper MP, Louisa Wall (Black Fern), Su'a Sio, Brendon Burns, Hamish McCracken, Denise MacKenzie, Max Purnell and Wayne Harpur. Yes, there are some on this list who might contribute more than some of those on the previous list. Yet these unsuccessful list candidates also stood unsuccessfully as electorate candidates. Can we say that one group of unsuccessful electorate candidates have more right to be in Parliament than another more experienced group of unsuccessful electorate candidates?

If we accept the argument that defeated electorate MPs should not be allowed to become list MPs, then what about other MPs who stood unsuccessfully as candidates in electorates? Should we class Katherine Rich, Georgina te Heuheu, Rod Donald, Jeanette Fitzsimons, Brian Donnelly, Clem Simich, Richard Worth, David Carter, Pansy Wong, Sue Bradford and a number of other re-elected list MPs as no more than a bunch of electorate losers?

MMP gives MPs who perform well at the national or at the local level some career stability. Yet the turnover of MPs is at least as great as it always was. The difference, for major party MPs, is that they live or die by their individual performances, and not by the magnified party swings that were once the bane of life for FPP MPs in marginal seats.

Life for minor parties' MPs is especially precarious, despite MMP. Heroic performances by such MPs – especially government-supporting minor party MPs – too often go unrewarded. The powerful major party dogs, like geckos, use and then ruthlessly discard their minor party tails. They expect to grow a new tail whenever they need extra numbers to build a coalition, to negotiate a support agreement, or to pass a piece of legislation. We, the voters, should all thank the minor party MPs for their tireless and principled dedication to democracy.