Standards in two key GCSE subjects have slipped, according to research to be published by the Government's exams watchdog next month.
Researchers for the Qualifications and Curriculum Authority found the standard needed to obtain a grade A or C pass in German was higher in 1987 than in 1997.
They said the level of writing demanded in the exam was no longer as high – although they conceded the oral part of the exam had become harder.
In addition, physics was judged to be easier in 1997, because of an increase in the number of questions requiring a simple recall of facts.
Next month, the authority is due to publish the results of an investigation comparing the levels of difficulty of seven GCSE subjects over the years.
However, the findings will also show that GCSE English became harder to pass between 1995 and 1998.
In 1998, all students were tested or required to produce course work on Shakespeare, whereas only one demanded this three years earlier.
The reports coincide with the row over exam marking standards this summer when Jeffrey Robinson, a principal maths examiner with the Oxford, Cambridge and RSA Board, claimed GCSE results had been deliberately "fixed" by reducing the grade boundaries. He was sacked this week.
The report on maths fails to back him up, saying standards have not changed.
The reports are the first hard evidence of any slippage in marking standards since the controversy. However, the authority said the overall picture showed little change.
Exam boards will be asked to review standards in German and physics as a result of the findings.
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