In recent weeks Ryan Coetzee, the Liberal Democrats’ director of strategy, has commissioned private polling from Survation in 100 marginal seats. This has allowed the Lib Dems to do a few things: They learn where to focus their dwindling resources more efficiently, they learn which methods of communication are working best for them, they learn which messages are most effective, and the ‘private’ bit allows them to only release the results where it is convenient to them (ie the ‘good’ news). There is good news, which is that they are very likely to win about 30-35 seats, whatever the national polls are saying.

Of course, because we aren’t stupid, we all realise that when they won’t tell us the results of polls in certain constituencies, it means that the results of them aren’t as positive. This would be why we know very little about what is happening in Scotland, where the national polls are suggesting the Lib Dems could get one seat, but rumours emanating from within the party suggest that the true figure is about five, with the main concern being whether Danny Alexander, the Chief Secretary to the Treasury, will remain an MP.

But back to the good news, which allows us to consider what is known as the “boomerang effect”, where voters for other parties in a marginal constituency (such as Labour voters in a Tory-Lib Dem marginal), switch to the ‘underdog’ party, as they might keep put the party notionally in the lead. A famous example of this was when Stephen Twigg, an unknown lamb to what was supposed to be a Michael Portillo slaughter in 1997 started polling well, leading to a massed joining of resources among both Labour AND Lib Dem voters to unseat one of the biggest Tory poster boys. If the Lib Dems can convince voters for other parties in their constituency that there is a chance they can win their seats and keep the Tories out then they could get both Labour and Green voters switching to push them over the edge.

Then there is the deeper information mined by Survation, which shows that the main switch to the Lib Dems in many constituencies comes from women and 18-34 year old Tory voters or undecideds. There has been a recent swing of sometimes over 15% among these voters. This shows that the Lib a Dems’ strong anti-cuts message is hitting home among those voters most likely to be hit by cuts (because the Tories protect older voters). It reminds everyone too that there is a strong argument that the most effective coalition partnership for the Lib Dems is with the Tories, where they are drag the party to the left in a search for ‘fairness’, rather than in coalition with Labour, where they would probably have to try and drag the senior partner to the ‘right’ in a search for keeping the deficit down.

The polling identifies a clear pattern to where Lib Dems are going to do well that just would not be spotted in a national poll. In national polls it is simply the percentage of people who are going to vote for a party in the election. But the Lib Dems at the moment would be fine with getting no votes at all in constituencies where they were never going to win if it means a rise in votes in the marginal constituencies it has a proper chance of winning. The national polls don’t identify where a Lib Dems already have an MP (and they are notoriously good, hard-working MPs) and control the local council (they tend to do this very competently). Where that is the case, the Lib Dems are properly ‘dug in’, and so will be harder to remove than we might at first think.

So, Norman Lamb, Tim Farron and Andrew a George are almost certain to survive. The Guardian also reports that there has been a major upswing in Cheltenham, St Ives, Cardiff Central, Eastbourne, Solihull, Cheadle, Leeds North East, Cambridge and Bermondsey.

The problems exist in marginal seats where the Lib Dems are contesting with Labour. There, they struggle to rise above the disillusionment of voters at them going into government with the Tories. This is a particular problem for Nick Clegg in Sheffield Hallam, which, despite being one of the most affluent constituencies in the area, has turned from a Lib Dem/Tory battle to one between the Lib Dems and Labour, with resources flooding in to try and unseat him. There, the Lib Dems are confident about Clegg’s chances, because they will be appealing to the Conservative voters worried about the chances of a Labour majority and reminding them that without Clegg the chances of the Tories back in number 10 are much lower.

It is true that it is very difficult to see the point of voting for the Lib Dems at the moment, due to the lack of a central message. The Tories have the economy, Labour has equality, Greens have the environment, SNP has independence and UKIP has Europe.

The Lib Dems have tried ‘stronger economy, fairer society’, to attempt to triangulate between the two main parties. But actually their best bet is to fight each constituency on its’ and their merits. They are good MPs, so vote for them. They are also the only serious Coalition partners without a particular axe to grind. Given a choice between the Liberal Democrats, who have shown themselves capable of governing in the national interests, and the SNP, who have shown themselves incapable of thinking of anything else but how they can have an independent country, the public may just prefer the former. The Lib Dems can only hope.