More than a third of primary schools rated as outstanding by Ofsted did not have top key stage 2 progress scores, according to a new analysis.

The research found that, of the 67 primary schools judged to be outstanding in the last academic year, 26 - more than a third - were not “well above average” for progress in reading, writing or maths.

And four outstanding schools had below-average progress scores in one or more of the three Rs.

The study by Education Datalab and the Association of School and College Leaders (ASCL) looked at the link between Ofsted inspection outcomes and progress scores at schools that had a full inspection in 2017-18.

Overall, it found a direct link between progress scores and inspection outcomes.

Education Datalab inspection researcher Philip Nye and ASCL inspections and accountability specialist Steve Rollett said: “What’s clear is that there is a strong relationship between progress scores and inspection ratings; schools with ‘well below average’ progress scores are some way more likely to end up with inadequate inspection ratings.”

But the analysis also identified a mixed picture among those schools that were rated as outstanding.

Of the 67 schools, 13 had well-above-average progress scores in reading, writing and maths. Another 13 had well-above-average scores in two of those areas and 15 were well above average in one area. There were 26 outstanding schools with no well-above-average progress scores.

Ofsted is introducing a new inspection framework from next year, which is expected to give less weight to a school’s exam results and data, and place more emphasis on the curriculum.

However, chief inspector Amanda Spielman has said that this does not mean “there will be no link between what we find about the quality of education, and what the published data says”.

The post by Mr Nye and Mr Rollett said: “This is a helpful reminder that, despite the narrative around the new framework, Ofsted argues that it will be evolution rather than revolution.

“While the links between key stage 2 outcomes and Ofsted grades that our analysis identifies may be expected to shift a little, it is unrealistic, and arguably undesirable, for the data baby to be thrown out entirely with the framework bathwater.”

They added: “Whatever form the next framework takes, it will be important to monitor its impact. Even with what appears to be some support for Ofsted’s direction of travel, few in the system will want to see significant volatility in inspection outcomes.”

An Ofsted spokesman said: “Exam and test data has only ever been a starting point for our school inspections. It does not tell us everything about what is going on in schools. 

“The new Education Inspection Framework, which will take effect in September 2019, will increase the focus on the substance of education, which is the curriculum, looking at how results are achieved not just the raw figures. We will launch a consultation about it early next year.”

The analysis by Education Datalab and ASCL has only looked at schools that had a full inspection in the last academic year

There were 2,591 short inspections of schools carried out in 2017-18, with 183 converting to full inspection status.

There were also 1,224 full section 5 inspections - giving a total of 1,407 full inspections altogether.

For these 1,407 inspections, the median 2017 reading progress score of the schools inspected was -1.3, while for writing it was -0.6, and for maths, -1.5.

The post added: “It is worth emphasising here that, because we’re not looking at short inspections that did not convert, we’re excluding the majority of schools that started off with a good inspection rating.”