What follows is a series of
quantitative thoughts on the election outcome. It is based on the 2017 election
night vote. Specials are likely to change precise voting shares and even seats.
However potential changes do invalidate the column’s overall conclusions.
Summary (which is less numerically
challenging)
– The share of the left has
returned to its long-term average after the disastrous 2014 election.
National’s share is only down a little. The centre was cannibalised.
– The big change 24 years after
the 1993 election is that National seems to have got 10 percentage point from,
essentially, Alliance voters. The other party shares are much the same
– By ruling out a Grand
Coalition, National is only as strong in negotiations as (or even weaker than)
NZF, despite having many more seats.
– The threshold rule for
entitlement to parliamentary seats (an electorate-seat or 5 percent of the list
vote) generates paradoxes.
– The Epsom deal with Act,
enabled National to filch a seat from Labour or NZF.
Long-term Trends
Basically, the left (Labour,
Greens, Top) got the same share of the votes as about its long-term average
(44.0%) over all the MMP elections (since 1996). The right was up 2 percentage
points (46.7% over 44.4%). It has done this by cannibalising the centre.
Compared to 2014, the 2017 voter
share of the left is up 6.7 percentage points, Labour share is up 10.7
percentage points at the cost of Greens. The right voter share (National, Act,
Conservatives etc.) is down 6.4 percentage points since 2014 but National is
down by only 1.0 percentage points.
2014 was the worst year for the
left since MMP began. In some ways 2017 is to Labour as 2005 was to National –
the unwinding of a disastrous earlier election performance.
The 1993 Election
My recent work in this area has
focused on the MMP regime which began in 1996. Previous to that there was a
Front-Runner system (often misleadingly called ‘First-Past-the Post’; there is
no electorate post). Voter share under FR, which comes only from electorate
counts, may reflect tactical voting. That applies today in the electorate vote
– a voter may prefer A but vote for B who has a better chance of getting rid of
a loathed C. However such tactical voting is less likely to happen for the list
vote. (Some may switch their list vote from a preferred main party to a small
party struggling to exceed the 5 percent threshold.)
I could not help noticing that
Sunday’s German election is scored for a win to Angela Merkel even though her
CDU/CSU party got only 32.9% of the vote. (Less than NZ Labour’s 35.8%.) The
SPD got 20.6% and Die Links (a party to its left) got 9.1%. The Greens got
9.1%, the centrist FDP got 10.6%, the far right AID 13.0% and others 4.09%.
That led me to reflect on the
1993 FR election in which National got 35.1% of the vote, Labour 34.7%, the
Alliance 18.2%, NZ First 8.4% and the rest 3.7%. So the left won the voter
share but because of the way the system worked, National became government by
itself.
The big change in the subsequent
24 years is that National seems to have got 10 percentage points from,
essentially, Alliance voters who were considered to be on the left of Labour
(it included Greens). The other shares are much the same. Quite an achievement.
Perhaps many Alliance voters of 1993 were actually covert National voters fed
up with Ruth Richardson and neoliberalism and were protest voting – in the
expectation that their vote would not matter?
The Banzhaf Analysis
Another feature of the German
election outcome is the expectation of a ‘Grand Coalition’ between the centre
right CDU/CSU and the centre left SPD – comparable to National and Labour. That
option is never discussed very much in NZ.
I turned to the Banzhaf Index
(sometimes coupled with Penrose or Coleman, who independently discovered it).
It is used to evaluate coalition possibilities and the consequential power of
the parties’ involved. I’ll avoid the mathematics and go straight to showing
how it is calculated for the New Zealand 2017 election.
Given the outcome there are only
four possible minimalist coalitions (in order of their parliamentary seats).
National-Labour
103 seats
National-NZF
67 seats
National-Greens
65 seats
Labour-NZF-Greens
61 seats
(These are minimalist coalitions.
ACT for instance, could join them but it would not affect that the coalition’s
domination in parliament.)
In the case of three of these
four coalitions, National is necessary. But Labour, NZF and Greens can each
prevent only two of the coalitions by withdrawing from them.
Add up the 3+2+2+2 = 9. The
Bazhaf index is calculated by noting that of these 9 possibilities National
involved 3 so its power score is 33.3% while the other three parties each have
a power score of 22.2%. So National remains ahead but by not as much as its
voter share. Moreover NZF and the Greens with much smaller voter shares are as
powerful as Labour.
You can complicate this by
assuming some coalition options are not acceptable. (Famously National was
ruled out as a possible leader of a coalition in 2005 because the Maori Party
considered Don Brash too racist – recall the ‘iwi vs kiwi’ billboard.)
For instance, if a Grand
Coalition is ruled out, instead of
N = 33.3; L = 22.2; NZF = 22.2; G
= 22.2
You get
N = 28.4; L = 14.2; NZF = 28.4; G
= 28.4.
So that by ruling out a Grand
Coalition, National weakens its bargaining power against NZF and Greens.
English hinted that National
might be open to an approach from Greens. Were National to rule that out, they
would be actually weaker than NZF for they would have only one option while
Peters would have two – which is the way the public commentary presents it.
(Act is as relevant to any
coalition forming as is the Maori Party.)
The Threshold Effect
To understand the actual
composition of parliament it is necessary to look at the eccentricities of the
threshold effect which says you have to win 5 percent of the vote or an
electorate-seat to be in parliament.
The current expected composition
is
Act 1, National 58, NZF 9, Labour
45, Greens 7.
Now suppose United Future had won
Ohariu (which would have been an overhang electorate) and the Maori Party had
won Waiariki. The outcome could well have been
Act 1, National 57, Maori Party
1, United Future 1, NZF 9, Labour 45, Greens 7 = 121.
Instead National may have to form
a government with NZF despite the latter having lost, apparently, some of its
vote to National. Moreover this became more possible because Labour won Ohariu
and Waiariki.
Strategic Voting and Act
Had Act not won Epsom the outcome
would have been:
National 58, NZF 10, Labour 45,
Greens 7 = 120.
So, in effect, National filched a
seat from NZF.
Suppose National had not done the
deal with Act, but United Future had won Ohariu and the Maori Party had won
Waiariki, the outcome could have been:
National 57, Maori Party 1,
United Future 1, NZF 9, Labour 46, Greens 7 = 121.
In this case the Epsom deal with
Act, enabled National to filch a seat from Labour.
(Note in all these calculations the swing (or last seat) is sensitive to
particularities and to special votes.)