Thinking about overhangs

The concept of the second choice of party vote should work regardless of overhang rules. But if the coat-tails rule is abolished, there is an increased risk of overhangs. The method chosen to handle overhangs can disrupt the proportionality of the result.

In general, overhangs arise when a party or independent candidate win electorate seats, but the St Lague system allocates them fewer seats.

There are several main ways this can happen:

  • A dominant party overhang occurs when a large and dominant party wins more seats than its party votes justify. This happens frequently in other countries, but is very unlikely in New Zealand. Conceptually this type of overhang could occur where a party is very dominant only within a small region, but such situations have not yet occurred in New Zealand.
  • A vote-splitting overhang occurs when voters vote for a candidate for one party and give their party vote to another party. This has occurred in NZ when voters have voted for Maori party electorate candidates and given their party vote to the Labour Party. This practice could theoretically be practised widely, so gaming the system and greatly distorting proportionality,
  • A threshold-driven overhang occurs only in the absence of the present coat-tails rule. It occurs when a party wins an electorate seat, but not enough votes to pass the 5% threshold.

In reality there are overlaps between these types of overhangs, so that rules are needed that work in a wide variety of circumstances.

The threshold driven overhang occurs only if the present coat-tails rule is abolished. In New Zealand there have been several situations where MPs have resigned from major parties and created their own party. This type of situation demonstrates an inconsistency between handling of elecorate and party votes. Independents can be lone voices in parliament, while parties are allowed only if they can get to six seats (5% of 120).

At present when an overhang occurs the party or candidate is allocated a seat over and above the normal 120 seats in parliament, and the proportionality of parliament is disturbed.

Another method of handling overhangs is to take the overhang seats from the seats otherwise allocated to list votes, so avoiding extra seats in parliament. Proportionality is disturbed, but often not greatly in NZ, as the overhang seats are taken from parties approximately in turn, and in proportion to their party votes.

This method is used in a similar electoral system in Scotland. There the overhangs are mostly of the dominant party type. As a result the overhang seats are effectively taken from other parties to give to the dominant party, so substantially disturbing proportionality.

The use of a second choice of party vote does not alter the overhang problems outlined above. Dominant party overhangs are unlikely in NZ and not serious, so can be safely disregarded.

A better treatment is needed of overhangs resulting from independents without supporting party votes. It is complicated by the ideal of representation i proportional to party votes whereas an independent has not party votes.

And the solution needs to work around the inconsistency between allowing single seats for independents, but refusing representation for parties with less than 5% of the national party vote.

Here is a sugestion that could largely eliminate the overhang problem. But I need to look more closely to be sure.:

  1. in electorate contests, there will be one winner. typically in NZ with 12-20k votes.
  2. All voters who gave their electorate vote to this winner , will have their party vote redirected to that winner s party. For an independent, the party is just the candidate them selves. The winner will receive one seat from their party s allocation, irrespective of the quotient.

This method should ensures that an electorate winner receives approximately the normal quota of party votes for their seat, and uses them to gain a seat.

In this way every seat requires a quota of party votes. And there is only a limited total quantity in the election.

This system makes vote counting more complex, because it is necessary to keep a total for every combination of party vote and candidate vote.

So there are things to check here. Does this work in every likely circumstance? How would you organise vote counting?

Based on a small sample, when there are about 40 000 votes, with two major candidates, the winner gains at least about 19 000 votes. With three major candidates, the winner often received about 13 000 votes. A typicalNZ general election has 72 electorates each with 40 000 votes on average. That means 40 000 electorate votes and 40 000 party votes. This corresponds to 2.88 million votes. If a candidate wins on 13 000, there will normally be two others at about 12 000 each , and about 3 000 among other parties.

More information to come

German lessons

It is commonly said that the New Zealand MMP system was modelled on the German PPR (personalized proportional representation). There may be lessons for New Zealand here. The language difference makes it more difficult to fully understand the diferences.

Here I will endeavour to explain the German system using terms familiar to those who know the New Zealand system.

My sources of information were:

The youtube video is easy to follow, but light on detail. The wikipedia page seems to use complex language, so is more difficult to follow, and uses many unfamilar terms. The Spiegel page is easier to understand but with less detail. And it is not clear just how accurate is the information provided in any of these. So this post should be read on the understanding that I have limited confidence in the details.

To improve clarity, I will refer to :

  • An assembly ( for NZ: parliament, Germany: Bundestag)
  • A mandate (for NZ: a (voting) seat in parliament, or MP, Germany: a voting seat in Bundestag)
  • Mandates can be district mandates or list mandates.
  • A district (for NZ: electorate, and <electorate MP>, Germany: district, elects a <direct mandate>, UK: constituency)

NZ and Germany both offer two votes, one for a district mandate, one for a list mandate. (German: direct mandate, <second vote>). NZ has 120 mandate assembly with 72 districts (72/120 = 60%), Germany a 598 mandate Bundestag with 299 districts (299/598 = 50%). Both systems allow overhangs to arise (a party wins more direct mandates than its party votes justify). This has happened a few times in NZ, with up to 2 additional overhang mandates. Overhangs seem more common in Germany. Germany has a complex system of <levelling mandates> to rebalance the assembly.

The German system has rules to deal with the numerous overhangs that appear there. New Zealand has had few overhangs, and so few special rules to govern them. New Zealand seems exposed to the misuse of overhangs to distort the proportionality of results

Germany has a provision that, where an independent is elected to a direct mandate, that party votes from the independent s voters are disregarded. This is to avoid those voters having double value in the election.

Both countries suffer from the problem that many voters do not understand the importance of the party vote compared with the district vote.

Germany has regional party lists, and a 5% national threshold. It is not clear how list candidates are allocated to list mandates. From which (regional) list is each mandate recipient chosen? Germany has constituent states. Regional lists seem to be lists for each state, but I am not certain

I have identified perverse effects of the 5% threshold in New Zealand, and have suggested a second choice of party vote to avoid them. I have not seen any reference to similar issues in the German system.

This page was last updated 23/10/21. Beware this post may not be accurate!

In the meantime, a two-choice NZ voting paper may look like this:

A possible two-choice voting paper layout, based on 2020 Hutt South

Beware of organised overhangs

MMP aims to allocate seats in parliament in proportional to voter support for political parties. Two-choice voting can remove most of the distortions that arise from the use of party-vote thresholds. But should an indpendent win an electorate seat, or a party win more electorate seats than its party votes justify, then an <overhang> is created. This, in the NZ system, is addressed by creating extra seats. The Maori Party has won overhang seats a few times.

But this system seems to invite manipulation, by electing independents who are not really so. A party would encourage candidates in safe seats to become independent <friends of the party>. The home party would not stand a candidate against them. These <friends> would be expected to win their electorate seats, and create an overhang.

A similar idea has already been used in Epsom, where ACT has been able to win the electorate seat, while National benefitted from the party vote. In this case, I think the move helped ACT pass the one-seat threshold for being allocated seats.

This idea might be acceptable in isolated cases, but imagine if major parties has a dozen of these arrangements each. The result could be 20-seat overhangs.

One might hope that the voters would reject such moves as unfair, and punish those practising it. Or it could become an accepted political manoeuvre.

I think that the current electoral system review should ensure that the rules make such manoeuvres more difficult. But this does not seem easily achieved.

One method would be to require, instead of votes for person and party separately, a single vote for a person and their party. Thus a vote for a Blue party candidate would also be a party vote for the Blue Party. Two-choice party voting would work well with such a system, except that the first choice would be for person and first choice party, the second for a second choice party.

See here for a Stuff article that mentions this issue.

A two-choice MMP voting paper might look like this:

A two-choice MMP voting paper might look like this

A second choice: like Supplementary vote for PR?

Supplementary vote is a voting system for selecting one person. Each voter may make a first and second choice (no more!). The top two candidates, on first choice votes, are retained. Where a voter voted for a candidate other than the top two, their second choice vote is applied, if it is for one of the top two candidates. This system is used for Mayoral races in the UK. SV is viewed as encouraging a more positive style of campaigning as candidates desire the second preferences of third parties.

Two-choice party voting has some similarities, except that it is used to measure voter support for parties under MMP. Parties passing a set threshold, on first choice votes, continue to the next stage, where they receive the second choice votes from voters whose first choice party did not pass the threshold.

Both of these systems are based on the idea that first and second choices are often clear in the voters minds. Using lower level preferences is less useful and makes complex many aspects of voting and vote counting.

These systems are simple, but get most of the benefits offfering preferences, while avoiding the complexity of multi-level preferences. Two-choice party voting means every voter can both vote for whichever party they wish, and have a say in the allocation of seats in parliament.

A two choice party voting paper might look like this (note itś simplicity!)

Review of electoral law announced

The Government has announced a major review of New Zealand s electoral law. This review will include addressing the problem of the 5% party vote threshold. There is a better solution than just changing the threshold percentage.

The 5% threshold as now implemented distorts voter and party behaviour, because of the fear of wasted votes.

Everybody hates this risk of wasted votes. A vote for a small party risks being wasted and hence playing no part in selecting which party gets to lead the next government. This is of concern to voters, to small parties, and to large parties, as it makes difficulties for all of them. Just changing the level of the threshold does not solve the problem.

Two-choice party voting offers a solution that is very simple and effectively solves the wasted vote problem, while leaving MMP almost unchanged. The only change is that it gives every voter a second choice of party vote . That just requires one extra column on the party voting paper. And one extra tick from the voter, if the voter wants.

If the voters first choice party fails to pass the threshold, then that vote goes to the voters second choice party. The wise voter strategy is to make sure that either first or second choice vote goes to a party certain to pass the threshold. From then on the MMP system works exactly as now.

This very simple change revolutionalises MMP, in a way that should please everyone. Every voter can support a small party if they want, and also be sure of having a vote that counts in the allocation of seats in parliament. Big parties can cooperate better with support parties, because there need be no wasted votes. The threshold percentage can stay the same or be changed.

Here is what the modified voting paper might look like

Scottish MMP/AMS elections 6 May 2021

I am writing this late morning on 7 May 2021 in France. There was an MMP/AMS election yesterday in Scotland. And there are no results yet, it seems!

We are fortunate in New Zealand, that General Election results are processed quickly, and we seldom if ever need to go to bed on election night without having a very good idea of the result.

The Scottish system is very similar to the New Zealand one, but is called AMS, for A-additional M-member S-system. Named because they (like NZ) elect constituency MPs then ‘add’ list members to create a proportional result.

The Scottish system differs in that Scotland selects list MPs in eight regions, so that each region has it own more or less proportional result. There are no fixed thresholds, but because each region elects only about 16 MPs, there is an effective threshold of about 8%. Scotland also uses the d’ Hondt method for allocating seats, whidh reputedly is more favourable to larger parties that the StLague system in NZ.

It seems a problem of many description of MMP/AMS that they talk about having constituency elections then about ‘added’ list MPs to achieve proportionality.

But as we know, it is the party votes that determine in MMP/AMS the overall makeup of parliament. So it is simpler to say that we use party votes to determine the overall number of seats in parliament for each party, and THEN fill those seats beginning with electorate/constituency winners, and taking the rest from party lists. (Noting that Scotland uses open party lists so that voters have a choice of list members, but voting papers are more complex).

Once you see it this way, the party votes are what you count first, because they take you straight to the overall result. By contrast the constituency and list results are of mainly local interest.

Two conclusions:
1. Descriptions of AMS/MMP should make more clear that it is party votes that almost solely determine the numbers seats in parliament for each party.
2. Once this is understood, it seems that Scotland could determine much more quickly the overall result of its AMS elections.

Comments relating to the New Zealand MMP threshold:

The use of several regions in Scotland makes for quite high effective thresholds. Many tiny parties have no hope of representation. The system might be made more proportional by having a fixed threshold and offering a second choice of party vote. That would allow every voter to vote for a party representated in parliament. The use of open lists in Scotland makes voting papers, and hence a second choice of party vote, more complicated than is proposed for NZ.

Inquiry into 2020 election

I have just learnt from facebook that the Justice select committee of parliament is holding an inquiry into the 2020 election. This is apparently something routine after each election. Unfortunately the closing date for submissions was 6 April 2021, so I missed it by a week or so.

From what I have read, the problem of wasted votes creates a barrier to participation in the electoral process. In the 2020 election, about 8% of party votes were disregarded because the voter voted for a party that did not pass either of the thresholds, being 5% or an electorate seat.

Young voters are likely to be interested in new ideas and new parties. But we have a system that disenfranchies anybody who votes for a party that does not pass one or other threshold. This disenfranchisement of minor party voters, perhaps mostly young voters, has a discouraging effect on voter participation.

MMP aims to be a proportional system. But bizarrely we have chosen to disenfranchise a small but significant proportion of voters by discarding their votes. This is a severe deficiency in our supposedly proportional electoral system.

And the problem is not one of the size of the threshold. Reducing the threshold would indeed reduce the problem, and eliminating the threshold would eliminate the problem.

But the problem can be better eliminated by giving voters a second choice of party vote. This solution means that every voter can have a say in the makeup of parliament, as well as expressing support for a minor party.

The two-choice system for party voting effectively decouples the size of the threshold from the issue of wasted votes. We can retain MMP with the threshold at whatever level we want, and still have a highly proportional electoral system.

A win-win solution to the threshold issue

The 5 per cent MMP threshold is regarded by many as the biggest problem in the New Zealand electoral system.  This problem remains perhaps because no solution has been found that satisfies two important interest groups.    One interest group wants the threshold reduced, because it leads to wasted votes and creates an excessive obstacle to new political parties.    But another wants to retain the threshold, because they fear a proliferation of small parties in parliament if the threshold were to be reduced.

There is a solution, one that arises from understanding some nuances of the apparently competing interests.  The interest group that wants the threshold reduced appears to be driven mainly by the desire to reduce the wasted votes that arise from a simple threshold.  The group that wants to retain the threshold is primarily concerned about avoiding a proliferation of small parties.

Seems to me there’s a deal to be made here.  Big parties get to keep the threshold percentage. Small parties get to see an end to most vote wasting.

What is exciting is that there is an easy way to achieve this.  Easy to understand, commonly used in the real world, easy to implement, ticks all the boxes.

Yes, the solution is to give each voter a second choice of party vote.  If the voter’s first choice party fails to pass the threshold, the vote goes to the second choice party.  So most voters would make sure one of their choices was for a party pretty certain to pass the threshold.

This proposal just requires a second party vote column on the party voting paper, and minor changes to vote counting.  Once we have totals for each threshold passing party, the existing seat allocation tool works exactly as now.

Just consider the pluses here. 

  1. Pressure to reduce the threshold percentage is lowered, making the big,  powerful parties more comfortable.
  2. A higher proportion of voters have a say in government formation.  We could go from around 92% to easily 99%.
  3. Nobody has to choose between voting for a minor party and abandoning the minor party for a major one so as to have a say in overall government formation.
  4. Minor parties probably get some more votes, because voters do not need to vote strategically, so the threshold seems less distant.
  5. Nobody needs to take into account the risk of wasted votes in any aspect of participation in an election.  That makes planning, and cooperation between like minded parties, much easier.
  6. Results would give a better indication of the real support for each party.
  7. The difference between a party just missing and just making the threshold cannot change the coalition-leading party.
  8. It is in many ways better than just reducing the threshold percentage slightly, because it puts a stop to all the perverse effects of wasted votes

So here we have a win-win solution to the long-standing MMP threshold problem.  And all at the small price of adding a column to the voting paper and inviting voters to place one more tick if they wish.

This idea may be useful in other MMP systems with thresholds.  Offering a second choice can be simply implemented and can help improve proportionality and encourage voters to express their real views.

Here is a mockup of a voting paper modified to provide for a second choice of party vote.

This is what the results table might look like, with the same format for everything between polling place and the whole country.

You can find out more about this proposal at

Have we been barking up the wrong tree?

New Zealand seems to have been barking up the wrong tree for much of the last 25 years looking for a solution to the MMP threshold problem.  No good solution has been identified, and MMP review recommendations remain unimplemented.  

But there is a very simple, easy to understand solution that keeps the threshold but eliminates the problems.

Give voters a second choice of party vote.  If a voter’s first choice party does not pass either threshold, their vote goes to their second choice party.    Voters are advised to make one of their  choices for a party that is certain to pass one of the thresholds.  Nothing else changes.

This solution is easy to understand, easy to implement, and does away with the problems.

Many, perhaps most, voters know which major party they want to see lead the next government.   Many also want to support a small party, but cannot know whether that small party will pass a threshold for gaining seats in parliament.  If they do not vote for the small party, nobody ever knows they supported it.  If they do vote for a small party that misses the threshold, they have no say in government formation.  Many voters struggle with this choice every election.

The second-choice system allows voters to clearly state the party they want to see represent them in parliament, but also have a say in government formation if their preferred party does not pass a threshold

The second choice of party vote requires a second column on the party vote part of the voting paper.  Once it is clear which parties will pass a threshold, each polling place can prepare its own results table.  Results for any grouping of polling places, electorate, region, island, national, specials, overseas, etc are easily obtained by simply adding up the results from the polling places involved.

Ideas like this were suggested by numerous submitters to the 2012 MMP review, and a few described a system in detail.  The proposal here is a little different in that it simplifies the allocation of second choices.  The message is to choose who you like,  for the first choice.  If you think this party might not pass the threshold, make a second choice for a party that will pass.

The second choice has the same limitations as the present vote.  The vote only counts if it is for a threshold passing party.

This change  takes away all the problems with the existing threshold.  People can express support for a small party, and play a part in deciding the next government.

Nobody needs to worry that votes for small parties may be wasted.  Even if a small party does not pass a threshold, its true level of support is publicly known, and its supporters still have a say in government formation.

This change considerably clears the air for everybody with an interest in the election.  Big parties get to keep the threshold they believe is important.  No votes need to be wasted.  Small parties are still excluded from being allocated seats in parliament, but their votes are recorded and their voters still have a say through their second choice.  The big problem of a party just missing the threshold and so changing the lead party in government is gone.  The system presents a much lower barrier to entry to small parties, while still preventing a proliferation of small parties in parliament.

The example results table shows a hypothetical situation where two small parties just miss the 5% threshold.  With the two-choice system, voters for those small parties have their second choices counted instead.

The size of the threshold is not the problem

Here is a comment placed after the following article:

The problem with the threshold is not so much its size, but the fact that votes, if cast for parties that do not pass one or other treshold, are wasted.

The wasting of votes in this way is widely hated, for well-known reasons.

Reducing but not eliminating the threshold reduces but does not eliminaate this vote wasting effect.

Reducing or eliminating the threshold prejudices the avowed purpose of the threshold – to discourage the proliferation of small parties in parliament.

The solution is one easily understood and widely used in many situations where we want people to make choices, and we want to ensure that almost nobody misses out. That solution is to offer each voter a second choice of party vote.

No need for a complex preferential voting system. Just a second choice eliminates the problems. Voters can vote first choice for their preferrred party, and second choice for a party which they think is certain to pass the threshold. If their first choice does not pass one or other threshold, their vote goes to their second choice.

This is easy to understand, easy to implement, and solves the problem.

More details at