The head of Britain's largest exam body is urging ministers to "go slow" on the drive for a single post-16 qualification and get the basic qualifications structure right first.
Tina Townsend, chief executive of Edexcel, said it was pointless arguing about a British baccalaureate versus an over-arching post-16 certificate before deciding how the range of study routes and qualifications now available could fit the new system.
Early evidence from the merger of the London exam board with BTEC to form the country's first unitary authority suggests that students are more willing to take the pick and mix package of A and AS levels, general national vocational qualifications and even NVQ units, if they are offered by a single board.
Typical combinations from the packages available are A-level English with GNVQ in business studies, or an A-level modern language with GNVQ in travel and tourism plus NVQ units gained through work experience at a travel agency.
Pilot schemes allowing 14-year-olds to gain NVQs at work were launched last year. There was considerable scepticism from education and some employers that 14 was too young to be doing assessment at work. But Ms Townsend said: "What really switches on young people the most is doing things in the workplace. One student with the English and business studies package had become far more articulate and confident than others. He spent time in India doing his GNVQ project helping the poor. "
Detailed evidence of the impact of the merger to form the single body will emerge next year, but the early anecdotal evidence leaves Ms Townsend in no doubt that such close alliances are essential before any decision on single post-16 qualifications.
The problem was not whether such combinations were worthwhile. "The problem is in the difficulty putting together a suitable package and the continued lack of equivalence of grades between the academic and vocational routes. The new AS level is not worth half an A-level but just 40 per cent. That does not help it to go with half a GNVQ."
The solution was to divide courses into smaller and more meaningful units which could more readily be mixed: six units, not 12, for a GNVQ, for example.
"All sorts of packages are now available and they inevitably improve the career options for school-leavers. Combining health and social care GNVQ with biology A-level opens the doors to a range of jobs from nursing and physiotherapy to social work and occupational therapy - far wider than the range of choices either A-levels or GNVQs would allow," she said.
More GNVQ Advanced students go into higher education than enter employment, according to a survey of student destinations carried out by Edexcel.
The study found that 54 per cent of pupils leaving school with GNVQ advanced qualifications continued their studies while only 41 per cent of their peers started work. Around 90 per cent of school-leavers with two or more A-levels go on to higher education.
Such a high staying-on rate for pupils completing GNVQs was a positive feature rather than a failure of the vocational course to prepare students adequately for employment, the survey's organisers said.
"We are talking about a group that historicall y has struggled at school or found it difficult," said Gordon Tempest-Hay, Edexcel's head of corporate affairs. "That such a significant proportion are continuing with their education is encouraging. GNVQs were always designed to be a way into higher education as well as a route into employment"
He estimated that around one-third of those going into higher education enrolled on the strictly job-related Higher National Diploma courses.
The survey, which analysed more than 7,000 responses from 360 schools, found that the proportion of intermedicate and foundation level students continuing with their studies was even higher, at 64 per cent and 77 per cent respectively. At each stage only 3 per cent left school without a job.
Edexcel plans to expand the survey this year to include data on the types of job and courses that GNVQ students go on to after their vocational studies.