In arguing that English schooling has outperformed Scotland, and speculatively attributing this to policies which encourage school diversity, my colleague Lindsay Paterson (August 7) dismisses Judith Gillespie's suggestion that the English improvement reflects declining exam standards "given the close liaison among the examining bodies and the need to maintain comparability of certificates".
However, the links between the SQA and its English counterparts are not close enough to prevent such divergence - nor could they be, given the different qualifications systems.
Moreover, the SQA's monitoring standards programme suggests that Scottish standards have remained broadly consistent, allowing for fluctuations across subjects. To my knowledge, the same cannot be said of English qualifications, and there is a widespread perception that standards have fallen (reflected in top universities' preference for Advanced Highers over A-levels, reported in the same issue).
A further reason for mistrusting the English "improvement" is the role of qualifications targets in driving the school system, which is much stronger than in Scotland. Goodhart's Law states that once an indicator is made a policy target, it loses its validity as an indicator. There is considerable evidence that English schools play the system, for example choosing qualifications which score more highly and focusing attention on pupils near the threshold.
The evidence on diversity and attainment is at best inconclusive. Linda Croxford and I compared attainment at 16 in England and Scotland over the period when policies diverged, from 1984-1999. We found similar trends in average attainment, but a narrowing of social inequalities in Scotland compared with England. Since then, inequalities may have declined slightly in England, but Ms Croxford's study (TESS May 22) suggests they also have in Scotland.
Stephen Gorard, whom Professor Paterson mentions approvingly in his letter, concluded from his detailed analyses of England and Wales that claims suggesting school diversity raises general levels of attainment were "sleight of hand".
I agree with Professor Paterson that these issues require further research. But until we have much stronger evidence that school diversity brings real benefits, we should not imperil the clarity of institutional mission and consistency of standards and provision across schools that are a hallmark (and, I believe, a strength) of Scottish education.
David Raffe, Centre for Educational Sociology, University of Edinburgh.