A young neighbour of mine can recite from memory the goal scorers for Croatia in the 1998 World Cup, the leading players in European football leagues and the order of merit in American basketball. When we see neat columns of well-marshalled statistics, we immediately assume we are looking at incontrovertible facts. It does not occur to us that different countries might count goals differently or that one nation’s season might last twice as long as another’s. We take statistics at their face value, and are comforted by their precision and reliability.

In education we have become accustomed to being bombarded with figures showing that teachers are getting older, that young people are becoming sexually active at an earlier age and that fewer pupils are taking school meals. We never question this received wisdom. The numbers say it’s true, and that’s that.

We are assured the whole world has been tested in mathematics and that we Scots are near the bottom of the heap. Beating our breasts in contrition, we resolve to do better, and get stuck into the hardest sums we can find to avoid being double-crossed by the rest of the world. Then we discover that the international surveys conducted were less than 100 per cent kosher, as countries varied enormously and ages for starting school differed across the globe. Why did nobody tell us that before they beat us about the head with the results?

Absence statistics produced by the Scottish Office, neatly divided into authorised and unauthorised, allowed one of the daily newspapers to identify “the 10 worst offenders”. These were, of course, the schools with the highest proportion of unauthorised absences. Pretty obvious, don’t you think? This conclusion overlooks the fact that authorities categorise absences in a variety of ways, and what is authorised in Glasgow may well be unauthorised in far-off Paisley. The absence rates also disable schools where headteachers and staff have done more than any of us to combat truancy, but where the size of the problem disguises the progress made.

Figures for school costs may mean something within a single authority, but across the country they have less consistent value, as the ways in which they are calculated are as numerous as the authorities themselves. When I am asked whether the figure published is correct for Holy Rood, I am at a loss to reply, as the statistic conforms to none of the financial totals I have to manage on a day-to-day basis.

The most flagrant example of spurious sums must be the recent survey of five-to-14 attainment. Schools were invited to base conclusions on the most recent National Test results, and if these were unavailable, on teachers’ assessments. These are very different things. In Holy Rood, English and maths staff went to enormous lengths to provide an objective picture. They were perplexed to find that other schools had used less rigorous approaches to assess performance. Finding that the teachers’ assessments were as varied as the teachers themselves, the Scottish Office sensibly took a step back and left authorities to deal with the resulting mish-mash. No competent teacher would put in a column of marks book scores for pupils who all sat different tests. It would be meaningless, and particularly unfair if used as a basis for comparing pupils.

Statistics are necessary to identify trends and to inform decisions on resources. We accept that they are often approximations, and should be treated as our slaves and not our masters. Lists of numbers can be impressive, and they can look very solid and objective, but, as all men discover, a good figure isn’t everything.

Pat Sweeney is headteacher at Holy Rood High School, Edinburgh