Thousands of students will collect their A-level results today, amid suggestions of a slight increase in the number of top grades being awarded and warnings of "greater volatility" in marks.
Analysis of the entry levels for the traditionally top-scoring subjects, such as maths, indicates the percentage of students achieving an A or A* will increase.
And the number of boys achieving the very top grade could pull further ahead of girls due to a rise in take-up of maths - typically a high-scoring subject - according to Professor Alan Smithers, director of the Centre for Education and Employment Research at Buckingham University.
Last year, boys held a 0.9% lead over girls at A* grade, although girls had a 0.4% lead at A and A* grade combined - having out-performed boys every year since the millennium.
Entries to maths and further maths in England are up again, with the former now overtaking English as the subject with the highest intake.
Since they award by far the most A* grades, this could lead to an increase in A* grades overall.
Prof Smithers said that the gap between boys and girls had been narrowing since 2006, and that boys could "go further ahead this year due to the increase in people taking maths and further maths".
Yet students are bracing themselves for greater volatility in this year's results because of changes to the curriculum, a teachers' union has said.
Chris Keates, general secretary of the NASUWT union, said that teachers and students had struggled to get to grips with new syllabuses which were brought in this year and could impact results.
The Government introduced changes to the subject content of all AS and A-levels last year. Mid-course exams were also scrapped, meaning that all exams are now taken at the end of the year.
Keates said the changes would particularly affect those receiving their AS-level results, as they are the first group to go through the new curriculum.
"Students and teachers have had a very short timescale to get to grips with the new syllabuses, particularly at a time when they have been trying to prepare for the introduction of revised A-level courses from next month," Keates said.
Russell Hobby, general secretary of school leaders' union NAHT, warned there could be "significant variation" in the results, with many students getting grades they had not expected.
He said that while the national picture may look "stable", the changes to the curriculum and examinations meant there could be big differences at a school and student level.
"For individual students, teachers and schools this is a real concern," Hobby warned.
"We are also concerned about the possibility of a further dip in the number of students taking creative subjects at AS and A-level."