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Andy Cooke on the UNS – Part 3

March 10th, 2010

UNS – Exploring the Distortions

I’ve put together a short series on UNS – what it is, what’s its track record, and what levels of distortion have occurred in recent elections. This is part three of three.

It is an article of faith that the electoral system is inherently biased against the Conservative Party. Certainly a UNS calculation from the position as of the 2005 General Election is very harsh on the prospects of the Tories. But is this built in? Even with a marginal boost unwind and tactical vote unwind, is there a residual tilt to Labour?

Let’s rephrase that. Was there a residual tilt to Labour?

In the run up to 1987, we can explore the distortion from a “level playing field” by simply invoking UNS from 1983 and plumping for a level score. We can see what lead each of the Big Two would need for a majority. To do this, I’ve held the Alliance/Lib Dem score at what they actually got, and varied the “Big Two” to keep their total share between them at what they actually got.

At level pegging, on 37.4% for Labour and Tories and the Alliance at their actual 23.1%, UNS says that this should have happened:

    Con Seats Lab Seats Alliance Seats Advantage
    307 297 22 10 to Conservatives

This is what UNS says should have been the requirements for various points of interest:

    Conservative majority Con lead 3.2%
    Labour majority Lab lead 5.2%
    Level on seats Lab lead 0.7%

The pro-Labour distortion is definitely not apparent. Indeed, the Tories have a distinct (albeit slight) advantage. The BES surveys from this time show a slight potential tactical vote against Labour, supporting the distortion, and it’s undeniable that Michael Foot appealed more to the Labour core than the floating voter – and it’s the outcome of 1983 that created this distortion.

In 1992, we invoke UNS from 1987 and carry out the same exploration. At level pegging (Con and Lab both on 39% and the Lib Dems on 18.3%), this is what should have happened:

    Con Seats Lab Seats Lib Dem Seats Advantage
    313 299 15 14 to Conservatives

This is what UNS says should have been the requirements for various points of interest:

    Conservative majority Con lead 2.6%
    Labour majority Lab lead 4.2%
    Level on seats Lab lead 1.0%

After 1987, the pro-Tory advantage increased – especially as the Lib Dem share dwindled. However, when push came to shove, the 14 seat advantage proved more than illusory – and the distortion not just unwound but wound up to Labour sharply – as can be seen when we look at the electoral landscape post 1992 – on the runup to 1997. Remember that the landscape used for UNS calculations for the next election is what actually was the case for the previous election.

From UNS from 1992, a dead heat in the polls should have given (with Con and Lab both on 37.9% and the Lib Dems on 17.2%:

    Con Seats Lab Seats Lib Dem Seats Advantage
    287 324 23 37 to Labour

Remember that 14 seat advantage that the Tories should have had? Well, at the 1992 election, it actually turned into a 37 seat advantage to Labour.

    Conservative majority Con lead 6.3%
    Labour majority Lab lead 0.9%
    Level on seats Con lead 2.6%

The same lead that would have given them a majority (under UNS) one election earlier would be not quite enough to draw level on seats in a hung Parliament. However, as events turned out, that 37 seat advantage to Labour (from a 14 seat advantage to the Conservatives one election earlier) proved to be eclipsed by the magnitude of what did happen. As can be seen when we look at what UNS from 1997 to 2001 says should have happened in a dead heat (37.4% each):

    Con Seats Lab Seats Lib Dem Seats Advantage
    252 340 37 88 to Labour

Blair outdid UNS rather handily in 1997, obviously. He’d have received a majority of 21 when level in the polls.

    Conservative majority Con lead 10.6%
    Labour majority Con lead 1.6%
    Level on seats Con lead 6.7%

This is where the distortions really became embedded. And just to add insult to injury, the distortions increased rather than decreased. Those who had lent Blair their vote tactically and those marginal voters who had decided to “give him a chance” could have been viewed as a provisional boost. That 88 seat distortion was a huge pressure on the electoral fabric – and the Labour first term did nothing to make them fear they’d made a mistake.

The 2005 landscape was fashioned in 2001. On UNS from 2001, a dead heat (at 34.7% each) would have given:

    Con Seats Lab Seats Lib Dem Seats Advantage
    207 351 59 144 to Labour

A dead heat should have given a Labour majority of 56. A 144 seat distortion advantage. Howard had no chance of winning a majority, realistically.

    Conservative majority Con lead 12.6%
    Labour majority Con lead 2.8%
    Level on seats Con lead 7.9%

And now? According to UNS, with the landscape that emerged from the 2005 election, a dead heat (assuming the Lib Dems on 20% and the Conservatives and Labour at 35% each):

    Con Seats Lab Seats Lib Dem Seats Advantage
    241 330 49 89 to Labour

Pretty much pegged back to the distortion that came out of the 1997 election. The milestone requirements bear that out:

    Conservative majority Con lead 10.2%
    Labour majority Con lead 0.4%
    Level on seats Con lead 6.8%

So in one handy table, let’s put up the changes in distortion from UNS. What was the seat advantage coming in to each election, and what did UNS say were the thresholds needed? And how did they change?

      Seat advantage Con majority Lab majority Level on seats
    1987 Con 10 Con lead 3.2% Lab lead 5.2% Lab lead 0.7%
    1992 Con 14 Con lead 2.6% Lab lead 4.2% Lab lead 1.0%
    1997 Lab 37 Con lead 6.3% Lab lead 0.9% Con lead 2.6%
    2001 Lab 88 Con lead 10.6% Con lead 1.6% Con lead 6.7%
    2005 Lab 144 Con lead 12.6% Con lead 2.8% Con lead 7.9%
    2010 Lab 89 Con lead 10.2% Con lead 0.4% Con lead 6.8%

Take a look at that variation. Bear it in mind when you use a UNS calculator. Read across from each election – that is what UNS said should be the case going in. The line below (the landscape seen in hindsight after the actual election was fought becomes that forecast for the next election) is what it actually was.