In a paper presented to a research forum last week, Roy Canning of the Institute of Education at Stirling University said apprenticeships had expanded largely by being grafted on to low-skilled jobs in a way that would not be recognised as apprenticeships in traditional occupations or in other countries.
Dr Canning, who investigated the system along with his colleague Iain Lang, also warned that all off-the-job learning for apprentices must be fully funded, which is the case at present only for specific skills. A national diploma in apprenticeship should be introduced with entitlement to day release at college.
"The shortcomings of the MA (modern apprenticeship) programme mean that the most able apprentices are drawn towards further and higher education rather than to pursuing careers based on apprenticeships," their paper states.
It found that the pattern of take-up of apprenticeships in the traditional, non-service jobs is much as it was in the past, based on recruiting young males directly from school. The authors describe this as "worrying" given the Scottish Executive's forecast that there will be a steady fall in the number of young people coming on to the labour market over the next 20 years. The service sectors are reaching out to a more diverse group, the research says, but there are "significant problems" of high drop-out rates.
The revelation of major weaknesses in the programme comes as ministers are pledged to increase the number of apprenticeships from 22,500 to more than 25,000 over the next three years. They have set aside pound;25 million.
Dr Canning and Dr Lang make a plea that the programme should be extended to older workers. At present it is open to 16-24s, with funding for those aged over 24 left to the discretion of each local enterprise company.
The researchers suggest that, as well as employer-led demand for apprenticeships, there must be a "supply side" expansion. Otherwise, "it is difficult to see how the present unregulated apprenticeship model in Scotland will survive over the next 20 years".
They point to "major concern" at the large numbers who give up before completing their apprenticeship, especially in "non-traditional" occupations outside the old heavy industries strongly associated with apprentices in the past. Non-completions range from 48 per cent in business administration to 60 per cent in customer services.
This represents "a significant loss to the programme", Dr Canning and Dr Lang warn. But the haemorrhage will not be noticed in the headline figure for the number of apprentices, because the Executive's target of creating more than 25,000 apprenticeships by 2006 refers to programme "starts" not to completions.
The study shows that there is a considerable way to go before key ambitions for the programme can be met, particularly opening it up beyond the traditional "heavy" industries and recruiting more females.
The Stirling research, which was funded by the Economic and Social Research Council, did not impress Scottish Enterprise. "We don't recognise the picture it presents, either from our analysis of the figures or the uptake," Alan Sinclair, its director of skills and learning, told The TES Scotland.
Mr Sinclair pointed out that the study was based on a very small sample and was at least two years out of date. Employers are making more apprenticeship places available and putting in more funding which is increasing each year, so they see the value of the programme.
A nationwide survey of apprentices, to be published next year, will show that they are also "very positive", Mr Sinclair said.