Exam board Edexcel says it is "certain" the standard of its qualifications are on a par with those of other boards, following an internal review.
Edexcel said it had found no evidence to support a chief examiner's claim that its GCSE geography tests were not as difficult as those of other boards.
It said it had analysed data from all five awarding bodies.
Pupils were no more or less likely to achieve certain grades with its exams compared with other boards, it said.
Edexcel, which studied data for GCSE geography, history and English, carried out a review after one of its chief examiners was recorded by the Daily Telegraph saying the geography course content was so small she did not know how the regulator had passed it.
Adexcel said the examiner had been suspended and regretted making the comments.
The Telegraph sent undercover reporters into 13 seminars for teachers held in London by various exam boards.
Two examiners from the Welsh exam board - WJEC - were also suspended after teachers at a seminar were allegedly told which questions would come up.
MPs on the Education Select Committee have called exam board heads to an emergency session next week.
Two inquiries have also been launched into the allegations - one in England and one in Wales.
In the Edexcel case, the examiner was recorded by reporters posing as teachers.
The paper says she said: "There's so little [in the course] we don't know how we got it through. And I'm deadly serious about that. When I looked at it I thought, 'how is this ever going to get through?'."
As part of its review, Edexcel said it had also assessed the "breadth and depth of the exam specifications" and was confident they were of the appropriate standard set by exam regulator Ofqual.
"As a result of this analysis, we are certain that Edexcel's qualifications are of the same standard as those of the other major awarding bodies," it said.