This week's GCSE results post-mortem began before there was even a stiffening body of evidence to work on. Leaked reports that there had been a deterioration in English and maths scores, for the first time in seven years, prompted some snap diagnoses.
David Blunkett, Labour's education spokesman, opined that the results had worsened because the 1995 candidates were the first cohort to have spent all their secondary years on the national curriculum roller-coaster. Other pundits claimed that it was a sure sign that standards were falling. If the English and maths results had improved yet again, it would, of course, have been an equally sure sign that GCSEs, like A-levels, are becoming easier: the schools and examining boards cannot win either way, it seems.
In the event, the overall pass rate was remarkably similar to last year's and the predicted fall in English and maths scores turned out to be more of a stumble - the proportion of candidates gaining A-C grades dipped by 1.3 per cent in English and 1.1 per cent in maths.
As these are only provisional statistics, it would be foolhardy to draw too many conclusions. It may be that the sharp drop in the number of qualified English and maths teachers reported this week has depressed the scores. But it is also possible that two less newsworthy factors are responsible for this year's results: the increase in the number of lower-attainers taking the English papers, and a slightly tougher marking regime.
London Examinations and the Southern Examining Group were criticised for awarding too many B grades to pupils taking middle-tier maths and science papers last year. The boards are still smarting from that criticism, and they and the other examining bodies will have been anxious to avoid another reprimand from the School Curriculum and Assessment Authority this year. As one exam board official said this week: "We're all singing from the same hymn sheet this year - and we're in tune."
The same cannot, however, be said of the country's leading independent schools following the publication of the report on the relative merits of co-educational and single-sex schooling by Professor Alan Smithers and Dr Pamela Robinson of Manchester University. The report was commissioned by the co-educational group of the Headmasters' Conference at a cost of Pounds 20,000, and was clearly timed to counter the thousands of pounds worth of free publicity that A-level and GCSE tables provide for single-sex schools.
Some observers will have enjoyed this rare public squabble among the ostensibly tight-knit independent school family, partly because it shows how cut-throat the competition for pupils is in the era of league tables. Others will wonder why HMC members have paid so much money to be told the self-evident truth that independent girls' schools owe most of their success to the fact that they admit so many able pupils from higher social-class backgrounds (an analysis of last year's state-sector A-level results has shown that there was no difference in the points scores of single-sex and co-ed comprehensives).
Smithers and Robinson, however, offer more than truisms and politically incorrect bar charts (the bars representing GCSE achievement are coloured pink for girls and blue for boys). Their report is a valuable review of the existing research evidence, but it is by no means an exhaustive tour of the territory.
There is, for example, no mention of the work by Dr Lindsay Paterson, of Edinburgh University, who has conducted a long, systematic study of gender differences in exams and concluded that there is no evidence that girls do better in single-sex schools. Equally, there is no reference to the recent Leicester University study of more than 1,000 secondary pupils which showed that single-sex schools do induce girls to adopt a more positive attitude to maths and science - at least in the junior years.
But, interesting though it is, research of this kind probably has little effect on parents' choice of school. Some will always contend that co-education is an essential preparation for adult life as it inculcates sensible attitudes about the opposite sex - others, particularly girls' parents, will never accept that the two sexes should be educated together during what Dr Peter Osborne, of Shenfield High, Essex, a pioneer of single-sex "streams" within co-ed schools, has characterised as "the silly years".
It is therefore a pity that research cash is not being used to answer more pressing questions such as: What can be done to tackle boys' underachievement and the yawning gender gap at GCSE? How can boys be disabused of the notion that it is not "cool" to work hard or to take "girlish" subjects? And why is it that although almost twice as many girls as boys earn a grade A in English at GCSE, young men are twice as likely as women to gain first-class degree honours in English? An answer to any of those questions would be worth very much more than Pounds 20,000.