The exams watchdog Ofqual says it expects a “small drop” in grades in some of this year’s GCSE science results.
The warning comes in a letter sent to schools in England, setting out plans for changes to GCSEs and A-levels.
The exams have also been taken by students in Wales and Northern Ireland.
The Department for Education said it wanted “high-quality” GCSEs and it was for Ofqual to “appropriately” set standards in awarding qualifications.
It is the first year a new version of GCSEs in biology, chemistry, physics, additional science and additional applied science will be awarded.
The watchdog says the syllabuses and exams for the subjects were changed because they were not tough enough.
“These GCSEs are designed to be more challenging, because the previous syllabuses did not adequately test the subject content and were not sufficiently demanding,” the letter says.
“Although we cannot be sure until results come in, we are expecting a small drop in achievements overall rather than anything more substantial.
“The picture may be different school by school.”
Brian Lightman, the general secretary of the Association of School and College Leaders (ASCL), which represents most secondary heads, said it was going to be a “very tough year” for students, especially if grades dropped.
“Students are working harder than ever before and their teachers are working harder than ever to do their best for them,” he said.
“It’s very demoralising for students to be told that the examinations they took were too easy.”
A spokeswoman for the Department for Education said: “We want GCSEs to be high-quality, demanding qualifications comparable to those in the world’s best-performing education systems.
“It is for Ofqual, the independent regulator, to ensure that standards are set appropriately in the awarding of GCSEs.”
Changes to these science exams were set in motion several years ago, before the election of the coalition government, which has since announced and made widescale changes to the exams system for England.
Education Secretary Michael Gove believed the existing system was not challenging enough and that it encouraged exam boards to “race to the bottom” in terms of standards.
The watchdog’s letter to schools sets out the planned changes and those which are still being consulted on. Ofqual has also set out a timeline to show when the changes are due to come in.
Pupils in Wales and Northern Ireland also take GCSEs and for now, education ministers there have said they do not intend to move away from the existing GCSE and A-levels, but the growth of divisions in the system could bring confusion.
I’m really not sure what the government are aiming for. It looks as if the government are trying to make England independent from the rest of the UK, with a totally different education system that is masquerading as something comparable to the rest of the world. What I don’t understand is we are achieving greater and greater results year on year, so why is the government tinkering with that, running the risk of these grades dropping as Ofqual predict? Instead of changing the curriculum and content, why not create one exam board instead of having several exam boards competing against each other? That way this ‘competitive dumbing down’ that Mr Gove speaks of wouldn’t happen as the exam board is monopolised.
As some of my regular readers will know, this year I’ve worked in a secondary school as a mentor to a GCSE girl, Hannah. I looked at some of the Physics and Biology practice papers that she presented me and some of those questions made me think ‘what on earth is this??’ This is a scary thought when you find out that I only did my GCSE’s 5 years ago, albeit Science was one of my weaker subjects. I dread to think what’s going to happen when this new curriculum comes in, if this trend does indeed continue.