We start by setting grade thresholds for the key grades for each exam paper. The grade thresholds for the other grades are set by using an arithmetic calculation.
For Cambridge IGCSE the key grades are always A, C, E and F. Once we have set these, we use arithmetic rules to determine the other thresholds for the paper (A*, B, D and G for Cambridge IGCSE).
We do not use norm referencing, in other words we are not trying to let the same percentage of candidates pass as in previous years. If the candidates are better than in the past, more will get through at a certain grade; if the candidates are weaker, fewer will get through.
We use a combination of professional judgement and statistical evidence when deciding on the key grade thresholds. Different sources of evidence are used to tell us:
- if the exam papers are easier, more difficult or about the same level of difficulty as last year
- if the candidates are better, worse or of the same ability compared with the previous year.
Once we have set the grade thresholds for each paper, we add them together to produce grade thresholds for the syllabus (or syllabus option for syllabuses with more than one route of assessment).
The sum of the threshold marks for each paper takes into account the contribution that each paper makes to the syllabus. A small reduction to the grade threshold may be made at the higher grades for statistical reasons that take into account the correlation of the papers.