The study, funded by the Scottish further and higher education funding councils, looked at four very different examples from Australia, the United States, the Netherlands and Ireland.
The conclusion is that too broad an approach, such as concentrating on changing people's attitudes, will dissipate the effort. The main emphasis should be on getting under-represented groups through the doors, which can have long-term as well as more immediate gains. This is described by the author, Maggie Woodrow of the European Access Network (EAN), as "jam today and jam tomorrow".
Ms Woodrow states: "Nothing, it seems, changes attitudes in higher education towards non-traditional students as much as encountering these students on degree programmes and seeing them succeed. And nothing, it seems, changes attitudes to higher education among non-traditional students themselves as successful role models with backgrounds similar to their own."
Ms Woodrow says this approach has been particularly successful at the University of California at Los Angeles (UCLA) which targets 30 community colleges with low rates of transfer to higher education. A series of initiatives persuades more students to take the university route, and then supports them to ensure they stay there.
The funding councils' study says the solution of creating single post-school institutions, which has been canvassed during the lifelong learning inquiry by MSPs, should be treated with caution. This has happened in Australia where a university and an FE institute came together to form the Victoria University of Technology, with around 50,000 students.
Ms Woodrow, executive director of the EAN at the University of Westminster, says this is a longer-term strategy and comments: "Abolishing the barriers between the sectors by abolishing the sectors offers considerable attractions, but there may too be some losses.
"A large dual-sector institution may itself present a more formidable initial barrier to participation by those from under-represented groups than a small, if lower status, institution of the community college type."
The study concludes that there is no one "best buy" for widening participation but states: "If the prime purpose of the collaboration is to avoid further delay in increasing participation in higher education by those groups which have already been excluded for far too long, a model which focuses its energies from the start at the main blockage points of progression to higher education offers the most immediate gains.
"It also . . . has the potential to achieve longer-term attitudinal and systemic changes, the impact of which will be less immediate but none the less significant."
Ms Woodrow recommends that a review should be carried out into the results of collaboration across the further and higher education sectors. The most successful ideas should then be funded.
Despite reservations about large institutions being a daunting prospect for some students, the study does suggest that mergers should be explored. Ms Woodrow notes that in Scotland, where FE already delivers a much larger proportion of HE courses than elsewhere in the UK, "the case for continued separation between the sectors is harder to sustain".
This may not eradicate a dividing line, however, since vocational HE courses are concentrated in colleges. The funding councils have been working on widening participation for some time, setting up a joint task group. The main examples of collaboration are the University of the Highlands and Islands Millennium Institute and the Crichton campus in Dumfries.