Headteachers have warned that the Sats results, due out today, should be taken “with a pinch of salt”.

More than 500,000 10- and 11-year-olds sat papers in reading, maths and spelling, punctuation and grammar (Spag) in May.

Last year just 53 per cent of pupils reached the expected standard in reading, writing and maths- a drop from the 80 per cent reaching the then expected level 4 in all three subjects in 2015 - after the tests were made tougher and teacher assessments were also altered.

The changes resulted in an outcry over how reliable the results were, and led to both Ofsted and the government saying that they would not use the 2016 data alone to judge whether schools were failing.

But concern remains that the system is not yet settled enough for today’s results to be viewed as reliable.

‘It’s not just about data’

Russell Hobby, general secretary of the NAHT heads’ union, said: “Currently, the methods to hold schools to account aren’t as fair or reliable as they should be. Sats data only gives parents part of the picture when judging a pupil’s success or a school’s effectiveness.

“At the moment, parents and schools know these results have to be taken with a pinch of salt. This can’t be right. Just looking at data misses the majority of the real work that schools do to help young people achieve their full potential.

“Schools do need to be held to account but inspectors should look at more than just data. That way, when parents are reading Ofsted reports they can have more confidence that the report properly reflects how good the school actually is.

“We are seeing the signs of a more balanced approach to the use of data by Ofsted, as expressed in a recent speech by Amanda Spielman, the chief inspector, in which she said, ‘Rather than just intensifying the focus on data, Ofsted inspections must explore what is behind the data, asking how results have been achieved.’”

The government has now proposed further changes to the primary assessment system, but the consultation on the changes only closed last month - after the 2017 Sats were taken.

The NAHT has also renewed its call to scrap floor standards and coasting standards for schools, saying they give too much weight to test data. “We need to remember that these results simply reflect how a small proportion of a school’s pupils performed in a one-off 45-minute test,” James Bowen, director of NAHT Edge, which represents middle leaders, said.

The number of schools below the floor standards will be published in December.

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