Editorial: School exam rankings are proper guide

League tables, teachers disparagingly call the list of school exam results we have just published. Supposedly they conceal more than they reveal, since they take no account of the "raw material" each school receives and thus provide no measure of the value the school has added.

It is a surprisingly mercantile criticism to come from a profession that normally condemns any attempt to treat education as a commodity, and it is overstated.

As the principal of St Cuthbert's College said in yesterday's edition, high marks are not achieved through good bloodlines or bulging bank accounts; they come from hard work and encouragement. Qualities of hard work and educational encouragement can be found more in some families than others but it should not be assumed that financially secure families are necessarily more attentive to their child's studies and work ethic. It is mainly the school that breeds a culture of success and it is schools such as St Cuthbert's - top of the table of the latest national exam results - that deserve the credit.

League tables are not published primarily for the edification of schools, though. They are published for the information of parents and caregivers who want to know how their child's school, or prospective school, is performing. If that information leads interested parents and capable pupils to seek out the highest-ranking schools, so be it. Success feeds on success in most fields of human endeavour. The point of the exercise, it bears repeating, is not to provide schools with a measure of the value they add, but to give the public a guide to centres of excellence.

Not all criticisms of the table can be easily dismissed, however.

There is always the suggestion that some schools, more concerned for their place on the table than providing all pupils with opportunity, discourage their less able students from sitting the examinations. The second-ranked school on the latest table, Cambridge High, concedes that its guidance counsellors suggest other options to pupils who are falling behind. There is no suggestion, though, that the school is acting in its own interest rather than the pupils'. In fact, it is hard to believe that any school systematically restricts examination entries for the sake of a notch or two on the table.

A more serious concern arises with the new national certificate of educational achievement, NCEA, that replaced School Certificate last year and is being introduced successively to sixth and seventh forms this year and next.

The NCEA gives pupils multiple chances to pass each level of a subject. And since much of the testing is done by schools internally, there is the suspicion that some schools will not account for failures, especially if the pupil plans to try again next year.

With the award of overall grade point averages there must be a temptation to exclude failed subjects from the calculation.

But generally the new examination method has not made a discernible difference to schools' results. A glance at the NCEA table suggests that the schools with the highest pass rates were those that did well previously, and did well again in the traditional Bursary exam.

Likewise, some schools languish in the new system no less than before. Many of them are receiving disproportionate funding to reflect the relative poverty of their rolls. The league table will reinforce their case for continued extra help, but it should also be a reason for questions to be asked about the use the schools are making of their existing special funds.

Once again, unfortunately, the most-sought-after schools are obliged to favour enrolments from their neighbourhood, which restricts the access of ambitious pupils from outside the zone. But even those with less choice now will benefit from the disclosure of the schools' results, because in every school these tables are the subject of anxious study.