The word “fix” appeared in several national newspapers last week. The TES led with its headline: “Teachers’ outrage at exam board A-level results ‘fix’”. The focus of that anger was OCR’s apparent downgrading of an unprecedented number of A-level papers, particularly English literature and history coursework.

My primary concern is a different but related form of fixing: defining consistent examination standards. In the past week, members of the Headmasters’ and Headmistresses’ Conference have sent me the following examples:

* A history student was runner-up for the Julia Wood Prize awarded by St Hugh’s College, Oxford. His essay was so impressive that they invited him to lunch. When the essay was submitted to OCR it got a C grade.

* Two boys got overall As by getting As in five units and Us for coursework; both pieces of coursework were A grade standard.

* A candidate turned down Yale and Oxford to go to Harvard. He has never got less than a top grade in anything. Historians who saw his coursework judged it to be among the best they had seen. He got a C for this module.

All three examples are worrying and hard to understand. With numerous other schools - not just in the independent sector - citing similar anomalies we have to ask: “What has gone wrong?”

The answer lies in the impossible task now facing the awarding bodies. They are required to achieve comparability between different modules or components (coursework versus an external exam), different subjects, qualifications in the same subject area between awarding bodies in the overall pattern of results and comparable year-on-year standards.

Even before Curriculum 2000 many of these Qualifications and Curriculum Authority code of practice requirements were already under extreme pressure. Following the introduction of the new modular A-level system, the availability of resits and the variable nature of the cohorts sitting different modules, something was bound to give.

On this occasion, the need to achieve comparability with last year’s results appears to have taken precedence over the need to be fair to this year’s candidates. In a letter to all principal examiners and moderators after the issue of results in August, OCR’s chief executive admitted: “The A2 unit standards finally established had to be more demanding than those originally recommended by many of our awarding committees.”

So standards were subsequently changed to achieve an overall subject standard consistent with the past.

With an A-level structure that now consists of six separate modules, standards can only meaningfully reside at individual module level. If the initial judgments made in relation to each of these are right, there can be little justification for changing the overall final result later, simply because it produces too many overall passes or too many high grades at A-level. If the profession, the public or ministers are not comfortable with the brave new world of AS and A2, in which candidates can systematically improve their grades as they go, then something will have to change.

For example, the uncoupling of AS and A2 (making them into separate qualifications like Scottish Highers and Advanced Highers) would obviate the problems inherent in trying to aggregate two different standards. To turn the A2 into a traditional linear exam (a single three-hour paper in most subjects) taken in June by all students completing A-level in any one year, would also simplify standard setting, at A2 at least. Tighter rules on resits (although unpopular in some quarters) would enhance manageability and further simplify standard setting. Given the messy and inconsistent hybrid of norm and criterion-referencing that has evolved over time, maybe we should report two sets of grades: A-E (entirely on a criterion-referenced basis), alongside 1-5 (a norm-referenced indicator of relative performance of the individual against that year’s A2 cohort).

While each of these would throw up its own technical problems, all are worth exploring. But what we need first, and most urgently, is a fundamental re-appraisal and public debate about what we now mean and understand by the word standards.

Without such a debate, allegations of “fixing” will join accusations of “grade inflation” as part of the annual examinations ritual every autumn. This year’s experience of the new A-level standard suggests not only that it is finally “broke”, but also that attempts to fix it retrospectively have proved to be both misguided and damaging, not only to individual students but to the credibility of the system as a whole.

Geoff Lucas is secretary of the Headmasters’ and Headmistresses’ Conference.