Three weeks ago Full Fact reported on general befuddlement in the press over Ofsted's report on pupils with special educational needs (SEN), which argued that pupils were being misdiagnosed with SEN when the focus should be on “improved teaching and learning for all.”

With expected spending cuts and the upcoming Education and Children's Bill, it is a vital time for SEN policy.

So when articles in the press split over whether reports suggested that half or a quarter of SEN students had been misdiagnosed, Full Fact decided to investigate.

We concluded that the lower figure was more accurate, and persuaded some outlets to correct their stories.

However, the confusion had originated with a lack of clarity from Ofsted. Did their estimate – and it was an estimate rather than a figure based on rigorous research – that “half of all pupils identified for School Action” were misdiagnosed include School Action Plus?

Different reporters had made different assumptions, and yet the watchdog refused to issue a public clarification, effectively denying responsibility for the media's misreporting of their figures.

As campaigners for accuracy and accountability, Full Fact disagreed. But when it was suggested by some journalists that they had been led to falsely believe in the press briefing that they were justified in including the almost 500,000 children on the School Action Plus scheme, Ofsted's laissez faire approach to their data became indefensible.

We pressed Ofsted for a clarification, and this morning we received a letter in from Chief Inspector of Schools Christine Gilbert.

She confirmed that findings about School Action should not have been generalised to School Action Plus, and that the report has fallen victim to “inconsistent reporting”. Ms Gilbert further indicates that the report found no widespread over-identification for School Action Plus - so claims to the contrary went beyond speculating on Ofsted findings, and actually contradicted them.

Ofsted assures us that they appreciate our concerns. But apparently they are not quite concerned enough to accept the need for public clarification of a figure that is likely to impact directly on policy decisions.

We will continue to press for public clarification from both Ofsted and those media outlets that have not yet corrected their stories, and will continue to update readers on our progress on Twitter and on the blog.