Keith Weller, SCAA's assistant chief executive for key stage 4, makes a spirited defence of the new system. "Most of the evidence suggests that it is very difficult to set written tasks which are genuinely differentiating between the lowest achievers and the high-flyers. That is why tiering is being extended in most subjects."
Although GCSE was brought in to mend the division between O-level and CSE, it was always intended to be differentiating and not, according to Mr Weller, "just a string of marks along a line".
SCAA now believes that there is little point in a pupil gaining an A-star at GCSE when he or she is understretched by 95 per cent of the questions. Concomitantly, it believes a greater sense of worth could be instilled in low-achievers by setting an exam more relevant to their ability.
"We want able pupils to feel 'Yes, this was tough' and I would say to parents, 'do we care so little for our lower-ability pupils that we would pitch them into an exam in which they have no toe-hold?' There is nothing more devastating than having expectations and then not being able to relate to the paper. "
SCAA dismisses objections that tiering heralds the return to a two-exam system. Unlike O-level and CSE, where decisions about exams had to be made in Year 9, it argues that as syllabuses for different GCSE tiers will be common and standardised - though higher achievers will go further - tiering decisions can be left to much later.
"There is a judgment to make," Keith Weller says. "But teachers are making decisions like this all the time. It is a proper, professional procedure. If we don't differentiate, then more will lose out."
The authority also believes the two-grade overlap in the tiering system (grades C and D) will provide some flexibility for borderline cases and refutes claims that the system will prove unjust to those who gain an unclassified because they fall one mark below the cut-off point for the top tier.
Borderline procedures will allow the chief examiner to review the work of those who fall below, but come within 1 per cent of the borderline cut-off point.
SCAA denies there is inconsistency in allowing history to remain untiered while English and geography become tiered, arguing that geography's conceptual base links it to science, which responds best to different questions being asked of candidates of differing ability. On the more vexed subject of English, it says that scripts in both history and English had been placed under scrutiny, and while it was found that common questions in history could elicit different levels of response, English depended on the "difficulty of language" of texts and sources.
WHAT THE FUTURE HOLDS
As a result of the Dearing revision of key stage 4, there will be new syllabuses in all national curriculum subjects which will come on stream in 1996, with first exams in 1998.
Under the new regime all national curriculum subjects will be tiered except for art, music, PE, history and religious studies.
Maths will have three tiers: Foundation G to D; Intermediate E to B; Higher C to A-star.
All other subjects will have two tiers: Foundation G to C; Higher D to A-star.
There will be no allowed grades.
Revised syllabuses for subjects outside the national curriculum will come on stream in 1997 with first exams in 1999. In all of these subjects, SCAA presumes there will be the two-tier standard arrangement, though current negotiations with exam boards may throw up exceptions.