STATISTICIANS have been ordered to explain why Scotland’s census response rate was far less than the other parts of the UK – amid accusations the divergence is down to “nationalistic belligerence” by SNP ministers.

Scotland’s census data, collected by National Records of Scotland (NRS), fell short of its 90 per cent response rate target – after the Scottish Government delayed census day for a year during the pandemic, putting the country out of sync with England, Wales and Northern Ireland.

SNP Constitution Secretary Angus Robertson decided to extend the deadline to return the census after an initial return rate of just 79%. After an extra £6m of public funds were spent, the response rate increased to 89% but still fell short of the minimum target of 90%.

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The census in England and Wales was carried out in March 2021, as was initially intended in Scotland and reported an overall return rate of 97%. The census in Northern Ireland was also carried out in March 2021 and also reported an overall return rate of 97%. The previous census in Scotland in 2011 achieved a return rate of 94%.

The Auditor General has now warned that lessons must be learned after the fiasco led to increased costs and additional work required of temporary staff.

In response to the low response rate, the Registrar General for Scotland established an independent group of census and data experts to provide extra assurance. It concluded that NRS had a “solid foundation” to continue to the next phase of Scotland’s census.

This involved an additional survey and drawing on administrative data. However, the low response rate means the NRS is more reliant on the use of this administrative data than planned.

A new report from Audit Scotland has warned the administrative data has included the Electoral Register, data on GP registration from the NHS, the school pupil census and student data.

READ MORE: SNP minister Angus Robertson admits delayed census led to lower response rate

The document stresses that “there is no single reason why the return rate was lower than planned”, but it warns that “it is important that NRS learn lessons from the collection phase to inform planning for future censuses”.

Stephen Boyle, Auditor General for Scotland, said: “The census is a vital data gathering tool that allows public services to be planned properly. “It’s important that National Records of Scotland establishes why the return rate was significantly lower than the other countries in the UK.

“Those lessons should be shared and will be crucial to planning for future censuses and surveys.”

Donald Cameron, Scottish Conservative shadow constitution secretary, said: “It was clear from the moment that the Scottish Government decided to hold their census on a different date from the rest of the UK that it would cause trouble.

“Now the Auditor General has confirmed that this led to increased costs and a worse response rate than any other part of the country.

“He’s right that lessons must be learned – and I would hope Angus Robertson has the sense to accept them.

“The first of these is that the SNP must never again allow manufactured differences to distort the proper conduct of government business, wasting public money in the process.”

Scottish Liberal Democrat MSP Willie Rennie added: "Ministers made significant changes including moving the census online and getting out of sync with data collection elsewhere in the UK. Then they refused to learn any lessons out of nationalistic belligerence.

READ MORE: SNP minister Angus Robertson issues 'fulsome apology' to MSPs over census delays leaks

"The SNP's botched census will have a knock-on effect on the delivery of government services for the next decade. The Government must complete the work demanded of them by the Auditor General and ensure that poor and excluded communities are not left behind."

A National Records of Scotland spokesperson said: “As is the case across the UK and many countries across the globe, NRS’s modern census will bring together data from the initial census returns, the census coverage survey and administrative sources.

“NRS will bring these elements together using statistical methods and will deliver the high-quality census outputs and population estimates required by users.

“NRS are conducting robust evaluation across the census programme looking at all aspects of its design and delivery to reflect lessons learned. An end-to-end evaluation report on the census programme will be published and laid before Parliament.”

The Scottish Governmnet has been contacted for comment.