A review has found GCSE and A-level exams have become easier over the past few years, prompting the government to warn of a gradual decline in standards.
The watchdog singles out geography A-level for particular criticism, as well as changes in the assessment of biology and chemistry A-levels between 2003 and 2008. "As a result, students did not have as many opportunities to show their higher order skills," says the report.
The regulator also criticises GCSE papers in biology and chemistry for reducing the content of the syllabus – although this was now being acted upon.
A spokesman for the Department for Education said: "Ofqual's reports show evidence of a gradual decline in standards."
As a result, he added, it left the exams short of commanding the confidence needed in the system.
"These reports show that in recent years not enough has been demanded of students and that they aren't being asked to demonstrate real depth and breadth of knowledge," he added.
"It is good Ofqual has taken action to strengthen GCSEs and we're committed to restoring confidence in all GCSEs and A-levels."
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