Census can provide good data despite lower than expected return rate, MSPs told

Scotland’s census can still provide “really good” data on the country’s population, the UK’s national statistician has told MSPs.

Sir Ian Diamond was asked about the return rate of the Scottish census as he appeared at a Holyrood committee on Thursday.

When census collection ended in June following an extended deadline, the return rate stood at 89%.

When the census in England and Wales was completed last year, the response rate was 97%.

Speaking to the Scottish Parliament’s Constitution Committee, Sir Ian said the Scottish census process is still ongoing despite the end of the collection phase.

Written evidence to the committee said administrative data is now being used to a greater extent than was originally planned by the National Records of Scotland (NRS) in order to calculate the final figures.

Speaking by video link, Sir Ian told the committee the initial target was for a 94% return rate in Scotland.

He said: “In Scotland, yes we are going further than we want to, yes we are having less precision than we would have estimated.

“But we are still in a position – if we can control for all the biases – to make estimates at a level that has been done elsewhere in the world.”

Other countries have had “bigger problems” with data collection than Scotland is facing, he said.

“This is not impossible, it is hard,” he told the committee. “Scotland now has some of the best people in the world advising it.

“As long as the administrative data are good, we can control for bias, we can maximise the precision of the estimates and we can get to a place where you have really good, useful population estimates which are comparable with those across the UK.”

Sir Ian is a member of an international steering group which advises NRS, as well as being the head of the UK Government’s Statistical Service.

He received a message during his committee appearance which led to him clarifying his remarks about when the final results of the 2022 Scottish census would be published.

This is expected to take place one year after the data collection phase ended, rather than spring 2023, he said.