Opinion polls show election result was hiding in plain sight

It was the election of inconvenient truths. The temptation to dismiss the data was too great. The only surprise was that we were surprised.

The story being told since late in 2015 by Irish Times/ Ipsos MRBI polls appeared, well, incredible. So at times we all decided to give the story an ending that seemed more plausible.

What were these inconvenient truths?

That Fianna Fáil could be closing the gap on Fine Gael after just five years in the wilderness made no sense. Yes, the party outgunned Fine Gael in the local elections, but these were only local elections. In an important election to form a government, surely voters would think twice about voting for Fianna Fáil.

For certain, voters would not be so reckless as to let Fine Gael slip any further. We all know even successful governments are given a kicking in midterm elections but, when push comes to shove, a party that has brought the economy back from the brink would be given the benefit of the doubt in a general election.

As for the gravity-defying feat of Independents, it was only a matter of time before voters put on their strategic hats and placed forming a government ahead of voting how they liked. Independents and smaller parties would eventually revert to the norm as voters came to their senses.

What about Labour? How could a party that had acted responsibly in government be decimated at the polls, left with only a handful of seats? Transfers from Fine Gael might save the day.

The Irish Times/Ipsos MRBI series of polls told us exactly what was going to happen. It was glaringly obvious if we just followed the trend.

In November last year the gap between Fine Gael and Fianna Fáil was 11 points. By early February this had narrowed to nine and with a week to go it was down to five. It was heading in only one direction. On election day the parties had almost converged.

For Independents and smaller parties, there was no evidence from our polls that their halos were about to slip. Their rise was steady, starting at 23 per cent, then 25 per cent, then 28 per cent with a week to go.

On the day and on trend they scored 29 per cent of first preferences.

In four out of our last six polls Labour was measured at 7 percent. On one occasion the party dipped to 6 per cent and on another it was at 8 per cent. The trend was flat but still a trend, so 7 per cent for Labour last Friday was entirely predictable.

Sinn Féin also performed perfectly on trend. Highs in the mid-20s had long since faded, dropping to 21 per cent in our November poll. The next poll showed Sinn Féin slipping to 19 per cent and our final pre-election poll revealed a further decline to just 15 per cent. Sinn Féin fell again in the final week, recording 14 per cent in the general election.

The election result was hiding in plain sight.

On this evidence it would be difficult to argue that Irish Times/Ipsos MRBI polls are not accurate. Yet again our pre-election poll was closer to the final result than any other published poll.

As pollsters we learn a lot from elections. It is only once every five years, usually, that we get to evaluate the effectiveness of our approach to measuring party support. What we have learned, or more correctly what we have confirmed, from the general election is that volatility is the biggest challenge ahead.

A pre-election poll a week out from an election will likely have less predictive value in future elections. If voters continue to be slow to engage with campaigns, waiting for an election event such as a debate to make up their minds, general elections will begin to behave like their more fickle cousins, referendums.

We have also learned that we should trust the data. Polls are the only scientific way of measuring public opinion and of avoiding argument based on personal opinion and bias. Asking a hundred interviewers to knock on the door of a thousand households in every constituency in the country will always get us closer to the truth, especially an inconvenient one, than we will ever get on our own.