Why Lib Dems don’t do as well as other parties

My post on election campaigns not mattering now seems rather quaint, with the Lib Dems surging in the polls. Of course this is not completely novel, the idea of a 3rd party ‘surge’ was enough ingrained in popular conciousness for Spitting Image to joke about David Steel ‘feeling’ it.

Anyway what is perhaps becoming more clear is that even if the Lib Dems have the same percent of votes as Labour and the Conservatives, they do much worse in terms of numbers of seats. Most of the calculators put a 30% each election as something like Labour on 300 seats, Tories on 200 seats and Lib Dems on 100 seats.

I explained this on Tim Worstall’s site by:

It’s not so much the disposition of the seats but the FPTP system itself, which simply favours geographically concentrated votes. So say the Tories take 60 percent in all southern seats, Libs 30 percent and Lab 10 percent, and the reverse is true in the north. Nationally if equal no. of seats in north and south then vote share is Con 35, Lab 35, Libs 30. But Libs have no seats.

I wasn’t entirely sure if this was right, but I think it is essentially correct – the Lib Dems’ support is too widely spread, and they do reasonably well in most seats, not especially well in enough. Here is a chart of each party’s % share of the vote in the 2005 election, starting with each’s seat where they got the highest share of the vote in % terms, and ending with their lowest. So the 1st point on the chart is not a particular seat, but for each party the share of the vote they receivedin the seat where they received their highest share of the vote.

The box shows the share of the vote – 40% and higher – that typically wins you a seat. Of the 614 seats won by one of the three main parties, only 45 were won with less than 40% of the vote. Similarly in only 32 seats did a party get more than 40% and NOT win.

So taking the 40% line, one can see the Lib Dims get about 60 seats, the Tories 200 and Labour 350 or so – about what happened.

Now let’s assume the vote share – 35.3 Labour, 32.3 Tory and 22.1 Lib Dem in 2005 – becomes 29.9 Labour, 29.9 Tory and 29.9 Lib Dem – not wildly dissimilar to some recent polls.

Now the first thing to note is that the % share of the vote when a candidate will typically win will fall, to something like 37%. This is simply because the Labour and Conservative share has fallen, and we are in a three-way tussle.

But again we can see a good estimate of how many seats each party will get from where their line crosses that 37% line – the Lib Dems about 150, the Conservatives about 210 and Labour about 280. Now this isn’t quite what the uniform polls predict, that is because of a variety factors such as boundary changes since 2005, the particular makeup of some seats whereby Labour can win with a slightly smaller share than the Libs and so on. But it does show us why the Lib Dems fail to match Labour. And basically it’s because their vote is spread reasonably evenly, with still high % shares of the vote in the last 200 constituencies, whereas the Tory and Labour vote has collapsed.

This assumes a uniform national swing (UNS), so the Lib Dems have gained 8% of the vote nationally since 2005 and will gain 8% in every constituency. What they need to form a government is for that extra 8% nationally to be concentrated in seats 200-400, where it would win them the election.

6 thoughts on “Why Lib Dems don’t do as well as other parties

  1. Britain’s first-past-the-post electoral system puts third parties with evenly spread support at a distinct disadvantage, but even so the Liberal Democrats had already come a long way in 2005 when they won 62 seats with 22% of the vote – nearly triple the measly 22 seats won by the Liberal/SDP Alliance in 1987 with an almost identical (22.5%) share of the vote.

    (To be certain, better targeting and anti-Conservative tactical voting have helped the Liberal Democrats in recent general elections, but the major factor behind the improvement is the collapse of the Conservatives’ share of the vote from the low forties to the low thirties, where it has remained stuck since Tony Blair’s 1997 landslide victory.)

    Interestingly, the various electoral calculators available online suggest the Liberal Democrats would emerge as the largest party in the House of Commons (albeit well short of an absolute majority) if they were to win around 37% of the vote, to 30% for the Conservatives and 24% for Labour. However, for the time being it seems hard to believe that the Tories could actually end below their 1997 election low of 31%; that Labour could do worse than the 28% it polled in 1983; or that the Liberal Democrats could have their best result since the old Liberal Party won nearly 30% of the vote back in 1923: the 26% share won by the Alliance in 1983 (excluding Northern Ireland) would seem a far more realistic figure for the Liberal Democrats. Nevertheless, they appear to have tapped a strong undercurrent of discontent at the right time, spawning a perfect storm which could conceivably sweep away with the old assumptions of British politics B.C. – Before Cleggmania.

  2. I saw one poll which, if translated into a uniform swing, would leave Labour as the largest party in the Commons with only the third-largest share of the vote; meanwhile the Lib Dems with a nearly 30% share would still only have 100 seats. I think this kind of result would really bring the defects of our system into focus. The 1983 election was also horrendously unfair for Alliance, getting about 4% of the seats from 25% of the vote, but the Tories had enough of a winning mandate anyway that the fate of the other parties didn’t matter so much. A hung parliament would be a different story, as we’d see endless argument in the media about ‘mandate’ as the three parties danced around all the possible coalitions, and I suspect any coalition that did form would have to work seriously on electoral reform.

    Another fun observation: I saw somewhere that if the 1997 election had been done under the proposed ‘alternative vote’ system (which tends to hurt the ‘Marmite’ parties who get few second-choice votes), then according to people’s stated preferences in polls, the Lib Dems would have ended up with more MPs than the Tories.

  3. Yes, 37% would give them a majority. Basically take the 2nd chart and increase the Lib Dem line (the orange one) by 7% points across the board, and you’ll see they cross the ‘winning line’ much further along.

  4. While I agree that the outcome of the upcoming general election in the U.K. may underscore the need for electoral reform, I wouldn’t rule out a near-proportional distribution of seats if the numbers and the swings fall in the right places (although I wouldn’t count on it either).

    And speaking of 1983, the folks over at PoliticsHome have updated their election projection, and they have Labour and the Liberal Democrats practically where they (or their predecessors) were back in 1983 in terms of share of the vote, but by no means in terms of seats – not the least because the Conservatives remain well below where they stood back then, and well short of an absolute seat majority (even though PoliticsHome relies on a more sophisticated model that’s less favorable to Labour seat-wise than the uniform swing-based electoral calculators).

    At any rate, ever since poll numbers began to narrow down a few months ago, I’ve been wondering if David Cameron will turn out to be the Tories’ Neil Kinnock – that is, the leader who seemed set to become Prime Minister and bring his party back to power under a more moderate image after thirteen years in the wilderness, only to come up short at the last minute because voters weren’t convinced that the party had become that moderate after all (as was the case with Labour in 1992).

  5. All interesting stuff. But the LibDem rise was on the back of one TV debate. There are two more to come – and the other parties will be giving more attention to the LibDem manifesto, etc.

    It’s only on polling day that we’ll know the reality.

    NB As a mere onlooker I hope the UK Parliament does become “hung”: there might then be some sensible voting reform.

  6. “I wouldn’t rule out a near-proportional distribution of seats if the numbers and the swings fall in the right places (although I wouldn’t count on it either).”

    I agree it wouldn’t be too hard, it requires on the second chart the lines to cross at much the same point, and really just needs the Libs’ surge to be concentrated on winnable seats, and the Tories Ashcroft money to pay off.

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