So how’s my scenario 3 – a Tory lead of 6% by May 2015 – working out then?

by Stephen Tall on April 2, 2014

Time to dust down a post from last December looking at scenarios for the 2015 election based on current polling – two of which pointed to the Conservatives being likely to take a poll lead in the next year.

(NB: as then, please note my huge caveat – “the extent of the polling science on display here is me playing around on an Excel spreadsheet.”)

In particular, I was curious what might have happen to my third scenario in the meantime. So pasted below is what I wrote in December, but I’ve updated the graph to add the last four months’ average poll leads to see how they fit the trend-line. (The answer is pretty well.)

Scenario 3

File this under the heading “a bit of fun… probably” – let’s look at the whole parliament and insert a polynomial trendline to take us through to May 2015. Here’s what happens:

tory lead in may 2015 scenario 3

Under Scenario 3, then, the Conservatives bounce back from their mid-term slump to lead Labour by 6% come the next general election. It couldn’t happen – could it?

By the way, if you recalculate the trend-line to include the last four months’ average poll leads, it still suggests a 6% Tory lead by May 2015.

Will the monthly average poll lead data points continue to follow this trend-line? It seems unlikely. As I’ve said before, I expect the polls to jump around a fair bit this year, especially around the Euro elections. But poll-watchers look at trends – and currently there’s only one trend apparent in the polls: a narrowing Labour lead.

Apart from my amateur polynomial trend-lines, there’s another criticism that can be flung at this quick and dirty look at the polls – that it’s wrong to focus on poll leads, far better to focus on the party poll shares. True enough.

But history won’t be much consolation to Labour here. The graph below is from this article – 3 early warning signs that Labour’s poll-lead drama is about to become a full blown crisis – by LabourUncut’s editor, Atul Hatwal.

It shows that opposition parties lose an average of 5.7% in support in the final year before a general election. The only time in the last half-century the opposition didn’t lose support in the final year before an election was 1983, as Labour had already reached their nadir in the immediate aftermath of the Falklands war.

Oh, and yes… for the record, the Lib Dems poll share remains 10%, where it’s been since December 2010. Consistency, that’s the watchword!

* Stephen Tall is Co-Editor of Liberal Democrat Voice, and editor of the 2013 publication, The Coalition and Beyond: Liberal Reforms for the Decade Ahead. He is also a Research Associate for the liberal think-tank CentreForum and writes at his own site, The Collected Stephen Tall.