Irish unity tracker: the poll of polls

How close are the polls to the majority required in support of Northern Ireland leaving the UK to trigger a Border poll?The 1998 Belfast Agreement, the landmark peace deal, stipulates that a Border poll – a vote on Irish unification – should be triggered if at any time it “appears likely” to the Northern Ireland Secretary of State that “a majority of those voting would express a wish that NI should cease to be part of the United Kingdom and form part of a united Ireland”.Ultimately, the decision over when to trigger a Border poll primarily comes down to the will of the people of Northern Ireland.But how should their “wish” be measured? And how does he determine whether it “appears likely”. Opinion polling points to a way forward.The Irish Times has collated a poll of polls on the question of unity, which will be updated regularly to track public sentiment in Northern Ireland.Including the latest polls, 48 per cent of the public favoured remaining in the UK when polls were averaged over the previous three years.Polls show 35 per cent of the public in Northern Ireland were in favour of a united Ireland, while 17 per cent said they either don’t know or were not sure.For more on the metrics that matter when assessing whether or not to trigger a Border poll read here.MethodologyTo assess public sentiment in Northern Ireland, The Irish Times amalgamated a number of polls on the question of a Border poll in Northern Ireland into a poll of polls to create a more robust estimate of the actual state of opinion over time on the question of a united Ireland.Polling data until 2021 was provided by the Working Group on Unification Referendums on the Island of Ireland. The Irish Times continues to update this data set, using what it judges to be well-conducted polls and surveys. A well-conducted poll is assessed as having a sample size of about 1,000 people and carried out by an experienced pollster or surveyor in the region. New polls will be considered along these criteria and assessed on a case-by-case basis.The trend line shows the overall direction of the various polls conducted on Irish unity. It does not smooth out or average the data; it uses something called linear regression that finds a straight line that minimises the distance between the data points in various polls and the line itself.Average poll results are also considered, and are included in a second chart that assesses the running three-year average of poll results in each category. A three-year average was chosen to represent a wider volume of polls in the average given the infrequency of polling on the topic.