I applaud the changes to the Primary School Leaving Examination scoring system ("New PSLE scoring system to have 8 grade bands"; July 14).

There are two ways that any exam can assess students.

The first is to benchmark each student's performance to everyone else's, by ranking them according to the distribution; the T-score system is one example of a ranking-based exam.

The second is about making sure each student achieves a level of competency or proficiency of the tested subjects. Driving tests are one example of a competency-based exam.

For instance, passing a driving test is about demonstrating that you are a competent enough driver to be allowed on the roads, and it would be absurd to rank drivers based on their performance and let only those in the top 10 per cent drive.

Under the previous T-score system, a pupil's relative ranking was all that mattered.

There was no good way to ascertain whether individual pupils, especially the academically weaker ones, had demonstrated an acceptable level of competency.

Now, via the new Achievement Levels (AL), the new scoring system encourages each pupil to achieve individual proficiency, while continuing to distinguish those who performed well.

At the same time, pupils no longer have to split hairs over every half a mark in order to gain an edge over their peers in getting into their secondary school of choice.

To be sure, one mark will still mean the difference between Achievement Levels. For example, a score of 74 is considered AL5 while 75 is AL4.

However, there has to be a cut-off point in any scoring system, and the new one is surely an improvement over the current T-score ranking system.

Under the current system, academically stronger pupils are sorted based on tiny differences that are highly unlikely to reflect any real disparity in ability or effort.

The new system strikes a fine balance: It encourages competency and well-roundedness in all subjects while continuing to reward excellent performance.

This does mean that stronger pupils who are weaker in one subject, for instance, mother tongue, may find themselves facing more stress at first.

Not all stress is bad, however; it is an inherent part of any competition, and achieving any real goal.

The goal to attain proficiency in every subject is an excellent one; "chasing that last mark" is not.

Lu Xinyi (Ms)