DfE apologises to primary heads for prior attainment error

The Department for Education has apologised to primary headteachers after incorrectly classifying pupils’ prior attainment, Tes understands.

The error means that progress could look lower than it actually was, but the DfE has sought to assure heads that pupil- and school-level progress scores will not be affected, and that any flaws in data will be rectified by the time of finalised classifications in December.

However, concerns remain in schools.

One head, who asked not to be identified, told Tes that school leaders use early, unvalidated data for various reasons, including self-evaluation, planning improvement initiatives and reporting to governors.

DfE apologises to primary heads

In a letter sent to heads yesterday, seen by Tes, the DfE said that pupils with a key stage 1 average point score of 8 had been “incorrectly” assigned to the higher prior attainment group - instead of the middle prior attainment group - and that this would be rectified in December when school-level data is validated.

Schools were told that progress scores would not be affected as a result of the error but that there would be an impact on their low, middle and high prior attainment breakdowns.

The DfE said: “Please accept our apologies for any inconvenience this has caused.” It advised schools to visit the Check Your Performance Measures Data help centre “as this will be updated on a regular basis”.

Tes understands that Ofsted has been informed of the error so that affected data is not used in inspections.

The DfE is also understood to have explained that it informed schools as soon as it became aware of the issue, and that data at this stage of the year is always provisional.

Tom Middlehurst, deputy policy director of the Association of School and College Leaders, said: “The DfE’s assurance that the problem will be rectified in December and will not affect progress scores is of some comfort.

“However, this issue will still leave schools with a headache in managing any internal reporting of unvalidated data. And the fact that this error follows the fiasco of delayed Sats results in the summer will further shake the confidence of school leaders in the whole process.”

Extra ‘stress and workload’

Sarah Hannafin, head of policy at the NAHT school leaders’ union, said: “School leaders flagged this issue with us as they rightly expect the data they are checking to be as accurate as possible and that the DfE’s internal processes will work.

“Such a significant error is deeply unhelpful and causes additional stress and workload for schools, which will have likely been planning to use this unvalidated data for improvement purposes and in discussions with governors, among other things.”

Ms Hannafin added: “This does nothing to restore trust in key stage 2 Sats following the debacle of the delay to results over the summer.”

One head told Tes of the “frustrating” issue that, while Ofsted will only consider validated data, schools may for now still be relying on inaccurate data during discussions with the inspectorate.

They said that headteachers may have to explain apparent trends in data to stakeholders who may not be aware of the error and that, whatever reassurances are offered, inaccurate data “is not a great look” for the DfE and “not helpful at all” to schools.

The head told Tes: “In this round of Sats, there have been issues with marking, results were released late and now the reported data is inaccurate. This does not help schools, who are already under huge pressure from the current accountability system.”

The data mistake acknowledged in yesterday’s DfE letter follows the late return of Sats results at the end of 2025‑26 and a delayed deadline for submitting marking reviews.

On the first day of Sats, in May, primary schools also experienced difficulties submitting attendance registers through the online assessment portal in the first year that paper registers were fully replaced.