Record numbers of sixth-formers are expected to have taken a dissertation-style project this year to help give them an edge in gaining a university place.
The figures, released just a week before A-level results day, show the number of teenagers completing the Extended Project Qualification (EPQ) is set to exceed 35,000, more than double the number who took it five years ago.
Headteachers said the qualification – which students take alongside A-levels – is becoming increasingly popular and can help to strengthen a candidate's university application.
Students taking the EPQ, which is worth half an A-level, choose a topic, plan and research the issue and present their results. Many show their work in a written report, although they could also put on a production, such as a fashion or sports event, or come up with a piece of art or design, or even create a computer game.
Figures published by the Joint Council for Qualifications (JCQ) show that 33,245 candidates took the qualification last summer, up 108 per cent from 15,958 in 2010.
It has proven slightly more popular with girls, with 19,967 entered in 2014, up 113 per cent on 2010, compared with 13,278 boys last year, which was up 101 per cent.
An analysis of the statistics also shows a rise in the numbers of students scoring good grades in the qualification, with a 39 per cent increase in A*-A grades, from 27.9 per cent in 2010 to 38.8 per cent in 2014.
The proportion of students scoring at least a C has risen by 23 per cent, from 64.3per cent in 2010 to 79.1 per cent.
Professor Alan Smithers, director of the Centre for Education and Employment Research at Buckingham University, said there was a belief that the EPQ would act as a tie-breaker for some universities to tell top students apart.
But this has become less important in the wake of the move to lift the cap on places, allowing institutions to recruit as many students as they like.
"The use of the EPQ by universities is patchy. Some are taking it into account, others are not attaching great importance to it," he said.
"More than that, as the limit on places at top universities has come off, the need to make difficult decisions between students with similar qualifications has lessened."
Malcolm Trobe, deputy general secretary of the Association of School and College Leaders (ASCL), said: "Extended projects are becoming more and more popular. They are liked by universities and can help to strengthen a candidate's application.
"They are phenomenally valuable in giving young people the opportunity to prepare themselves for university where they will spend much of their time studying and learning through their own research and reading.”