Michael Marsh, Emeritus Professor, Trinity College Dublin, takes a look at party support over a three-year period.

Since the last election we have had more than 55 published polls from the main companies, tracking the varied fortunes of the parties through an eventful two years.

Most of those were done by RED C for the Sunday Business Post, and Behaviour and Attitudes for The Sunday Times, with eight from IPSOS/MRBI for The Irish Times, five from Millward Brown/Independent Newspapers and four from Ireland Thinks/Irish Daily Mail.

Of course, we can look just at the most recent polls - there have been three this month including today’s RED C survey - but with the reality of sampling error and events often having a very short-term impact it is more sensible to take a longer view if we are to estimate the standing of the parties with a view to the next few months.

Here I look at the polls over a three-year period starting in February 2015, which includes the run up to the last election and the two years since that vote.

I have shown first the trends for the three larger parties, Fine Gael, Fianna Fáil and Sinn Féin, and for the very diverse group of Others.

The graphs show each poll, a trend line as well as a dashed line indicating the level of support won by that party or grouping at the last election.

I will start with the main Government party, Fine Gael. What a difference a year makes! Its support looked as if it was rising in 2015, but it fell in the wake of the 2016 election and early in 2017 almost all polls put support below the 26% obtained the previous year.

However, the trend now is very much an upward one. All polls after March 2017 have suggested support above 26%, and almost all since late summer have put support at above 30% (the exceptions have been two RED C polls last year).

Support now is higher than it has been at any time since 2011. We often see government parties heading downwards at this point in the election cycle but Fine Gael is resisting this norm.

Of course, an obvious reason for this is Leo Varadkar, who is enjoying personal popularity not seen in Fine Gael since John Bruton was Taoiseach.

Arguably though, the upturn preceded Leo’s arrival; it started as Enda’s promised departure grew more concrete.

The continued economic recovery and fears about Brexit, together with fresh leadership are all factors, even without the perceived power of the Taoiseach’s new 'spin' unit.

Good news for Fine Gael is rarely good news for Fianna Fáil and this again is largely the case.

The party enjoyed a resurgent 2016 when almost all polls showed the party well up on pre-election support and above its actual election performance, but the trend through 2017 has been a slightly downward one, leaving it now in the mid-20s, just above its general election level.

A year ago Fianna Fáil was polling much more strongly than Fine Gael and it seemed as if Fianna Fáil had the best of the confidence and supply deal, having an influence on Government without carrying direct responsibility.

Now Fine Gael is clear again and Fianna Fáil support is in the doldrums.

Sinn Féin support has been flat over this whole period, although the party has consistently polled above the 14% it won in 2016, with no polls indicating support below that in the last year.

All four polls carried out last February put Sinn Féin at around 20%, but that unanimity has not been repeated.

The party will of course be hoping that Mary Lou McDonald will work the same magic for Sinn Féin that Leo has apparently achieved for Fine Gael.

It is still far too soon to know one way or another, but we can say that Gerry Adams' promised departure in itself did not provide any boost.

The other major change is in the support for 'Others' - the smaller parties, Labour, Solidarity, Greens, Social Democrats and independents within and without alliances.

This has trended downwards since February 2016, and it is now eight percentage points down on the vote achieved at that election.

If we exclude Labour from this group and look at the pattern of support over a longer period there is a consistent rise from 2008 onwards to a peak in late 2014 when support was higher than that for either Fine Gael or Fianna Fáil. This has been followed by a steady decline.

Over this same period of decline, since late 2014, the combined vote for Fianna Fáil and Fine Gael has risen from well below 50% to over 60%, signalling greater confidence in these traditional parties of government.

A few polls give the two parties the support of almost two out of three voters, a situation not seen since the banking collapse.

Within this broad grouping we see either little change or we see decline.

Labour support is around 5% and shows no signs of pushing back up to traditional levels.

Solidarity is polling below the 5% won in 2016, Independent Alliance is below its election 4% and Social Democrats and Greens each below their former 3%.

Different companies approach the measurement of support for these smaller, mostly newer parties (though not including Labour) and independent groupings in different ways, some mentioning all of them in their initial question and others providing a more limited list of options initially but subsequently prompting for details.

RED C have a longer initial list and this may be why they have tended to estimate around 6% more support for Independents and smaller parties combined since 2016 than have other polls.

All these graphs show the vote won at the last election in the form of a dashed line and for Others, as with the three parties, the polls were not always right, and certainly not right on average.

Fine Gael was overestimated, as was Sinn Féin and Others, while Fianna Fáil was underestimated. We can contrast current levels of support with those in the polls two years ago.

Fine Gael are ahead of where they were, Sinn Féin is at much the same point and Others have declined very significantly, while Fianna Fáil are well ahead of their pre-election poll standing.

However, it would be unwise to assume that 2016 would necessarily be a good guide to apparent polling biases at the next election.

Companies do alter their methodology from time to time as they try to ensure more accuracy, and late campaign shifts favouring one party or another can differ a lot from election to election.

If we do take these poll standings as accurate, where would this leave the parties in a general election?

Assuming 160 seats in the next Dáil, support for Fine Gael translates into 62 seats (+12), for Fianna Fáil 47 seats (+2) and Sinn Féin 24 seats (+1), with Others winning just 27 (-14).

This would certainly be a very different Dáil in some respects, but we would still see the largest party well short of a majority and without an obvious partner or even set of partners, to make up that shortfall.

Some commentators suggest that recent polls increase the chance of an election later this year, not least because Fine Gael might hope to cash in on their leader’s current popularity.

Fine Gael is well ahead of Fianna Fáil, but not much more so than it was during the 2016 campaign, and it is only a few months since there was nothing between them.

We are some way away from a situation in which another election could give us a definitive result.