The recent Universities Scotland report, on which you carried a most lucid editorial (February 13), may be admirable as an exercise in capturing headlines. As a balanced weighing of the evidence, it is not something that might safely be put before a policy-maker seeking enlightenment.

There is, as it claims, some evidence that increasing the amount of higher education in a country might lead to growth of the economy. But, as the one named author whom the report cites (Gemmell) has pointed out elsewhere, “the direction of causation is unclear”. It is as plausible that rich countries choose to invest in universities as that investment in universities makes them rich.

The report, moreover, castigates the allegedly weak economic effects of HNDCs on the basis of what might charitably be described as impressionistic evidence.

No attempt seems to have been made to assess statistically whether what matters is the level of the award or the prior characteristics of the students. No attention is paid to the potentially distorting effects of selective migration into and out of Scotland. No attention is paid to the quality of HNDC programmes of study leading to the awards.

Above all - in the light of the report’s central focus on economic growth - no evidence is cited on the extent and manner in which HNDCs might enable people who would not otherwise study beyond school to contribute to growth. Perhaps more rigorous evidence does exist. But, if so, it ought to have been cited.

Policy-makers are entitled to expect some rather more scholarly tentativeness from a body purportedly representing universities.

Lindsay Paterson, School of Education, Edinburgh University.