Grade descriptors
Grading by component
The exams are criterion-based rather than being norm referenced. In theory (although it is very unlikely to happen in practice!) all IB Diploma chemistry students worldwide could achieve the top grade of 7. The level of performance that each student must be able to demonstrate in order to achieve a particular grade is set out clearly in the Group 4 Grade Descriptors. Based on these descriptors the senior examining team at the Grade Award Meeting determines the minimum mark that a student needs to achieve for each of the four components (IA, and Papers 1, 2 and 3). Of course very few students will meet all the characteristics listed for a particular grade. What the examiners do is to try to place the students in the grade that most accurately matches their performance. Once the boundaries are set for all the four components the marks are then aggregated to provide the minimum overall percentage that students require for their overall IB grades 1 - 7.
The grade descriptors were actually first formalised way back in 1999. Before that they were simply vague descriptions such as excellent, very good, good etc. It was the biologists who first used more detailed descriptors. Their informal grade descriptor for Grade 1 used to be simply ‘breathing’.
The current Grade Descriptors (which are the same for all Group 4 subjects) for Grade 7 and Grade 4 are given below.