Every August when schools receive their pupils exam results, she effectively gives up a week of her holidays to analyse the data, discover which pupils have performed above or below expectations and apply any lessons to the following session.

Parents and school boards are likely to become more and more aware of the performance of subject departments. Detailed information compiled by the inspectorate for individual schools, entitled How Good Are Our Results?, accompanied the exam tables for the first time last year, and will gradually begin to make an impact. The levels of sophistication and systematic investigation grow by the year.

Like the school-by-school tables, the subject-by-subject data tracks the progress of pupils in individual subjects over three years. It provides three pieces of information the value-added progress made by pupils from Standard grade to Higher as compared with all other pupils in Scotland, the relative ratings which compare pupils attainment in different subjects at Standard grade in the same school, and relative ratings for Higher.

Analysing results is not the straightforward exercise it might seem. For a start, subjects like chemistry have different elements, as it were. Ms Fergusons analysis has therefore to focus on knowledge and problem-solving as well as the overall subject performance (the third ingredient, practical skills, is internally assessed).

We start with each individual pupil, Ms Ferguson says, by checking to see whether our predictions match their results. In cases where their performance is worse, we take a close look at our methods of assessment the prelims and the tests we administer. We do this for both Standard grade and Higher.

Its not just a matter of keeping an eye on the subject overall. We also check each level achieved at Standard grade and Higher, and compare the percentages on a yearly basis. For example, if there are more A passes at Higher, is it something to do with our practice, is it the pupils, or are some teachers pulling up the grades. If so why?

Earnock High offers some pupils targeted exam support from January to March, which exposes them to the best teachers (defined by the school as teachers who have the best ideas, who have shown good practice in the classroom and who have the right attitudes to young people).

Departments have to bid against each other for the extra cash available under the scheme which is for borderline cases not only those who might fail the exam but who could gain a better grade with a bit more effort and confidence-building.

The chemistry departments next step is therefore to look at the performance of these targeted pupils and discover whether the efforts have been successful.

Ms Ferguson says if the teaching is judged to be weak in any area, the methodology comes under scrutiny and, if necessary, changed. If the teacher is seen as the problem, he or she comes under scrutiny and, if necessary, changed. Both have happened, she adds.

A small example of altered methodology was the discovery by one teacher that Higher pupils were more at ease with drawing chemical structures in their jotters than constructing models although, again, that would not be appropriate for everyone.

The results also point up whether teachers are well-matched to particular classes. Earnock High tries to minimise this at the outset of each session by consulting on which teachers should be given which classes.

But, if the exams analysis shows some teachers would be better suited to work with groups on modular courses than on Highers or are particularly skilled in imparting the theoretical aspects of Standard grade chemistry, they will be moved accordingly.

The pupils views are taken into account although Ms Ferguson stresses, we are a bit more subtle than simply asking what do you think of Mr or Mrs X? If pupil or class results from school tests are out of line with expectations, these are entered into the equation to see if improved pupil-teacher relationships could be part of the answer.

Ms Ferguson acknowledges that the relative ratings which show subject performance within a school are useful if a bit difficult to understand.She adds: The fact that they are relative means that, if one department is performing strongly, another appears to be doing less well by comparison. This can be very demotivating for those teachers who may be working just as hard.

They might be driven to feel there is no more they can do, although it can sometimes be useful for them to rethink their approaches. On the other hand, departments doing relatively well can become complacent.

As ever, there are as many swings as roundabouts in the examinations industry.