NEW Grade boundary chart
The November 2020 exam session finally provided a clear idea of what the grade boundaries will be like under the 2018 Subject Guide. At last, the senior examiners in each component had a chance to analyse and assess the overall performance under the new system. This meant applying the new Criteria and Grade Descriptors to real student responses to real examination papers in the case of Papers 1 and 2; and to performance in the tasks expected in the Oral Internal Assessment. (By the way, grade boundaries for Oral Internal Assessment are fixed since the task involved in the component doesn't change from one session to another.)
It was thought to be unlikely that there would be any grand change from the kind of grade boundaries that had been normal under the old system (the 'legacy' system, to use current IB jargon). Apart from the introduction of the Listening Comprehension element in the new Paper 2, the rest of the testing mechanisms are virtually the same as the old ones, up to 2019. In addition, the IB holds to the principle of maintaining a certain consistency of standards in the change from one assessment system to another.
... the grade boundaries that emerged from the Grade Awarding discussions in the November 2020 session turned out to be slightly more generous in Paper 1 Writing and Paper 2 Comprehension - and this resulted in noticeably more generous grade boundaries in the final total out of 100. For instance, the bottom mark for a grade 7 was 83%, as opposed to the previous boundary of around 87%.
... the major disruption to normal teaching and examining caused by the COVID pandemic, everywhere, was a significant factor in deciding the setting of grade boundaries. The IB authorities chose to be generous (correctly, in my view) - wherever there wasflexibility about deciding a grade boundary, they went for the lower, more inclusive, figure. Accordingly, the N20 grade boundaries should not be seen as definitive for future exams - as the impact of the pandemic diminishes, and things get back to normal, boundaries will rise slightly, as the usual rigorous standards are applied.
In the meantime, here is a rough chart to help you to convert marks into grades.
NOTE: This is not an official IB chart - just my personal estimation
In all cases here, you can assume that grade boundaries may vary by +1 or -1 ... but for the sake of providing grades during the course, these figures are, I believe, within the range of variation which will apply in the real marking.
And let us never forget that the boundaries are notoriously imprecise. The difference between a script which is at the very top of Grade 5 and a script which is at the very bottom of Grade will be very slight indeed ... and very debateable as well! But in the end, in order to have grades, we have to draw lines between grades - and very often those lines are placed on the basis of very tiny distinctions, so tiny that they are barely detectable!
Adjusting for overall percentages
You can use the chart above to calculate how to transform marks into grades for the various different components, thus:-
Paper 1 Writing - the 30 marks column
Paper 2 Receptive skills - overall, the 65 marks column
** Listening = 25 marks column
** Reading = 40 marks column
Oral Interview - the 30 marks column
But... the marks available for each component are not the same as the percentage weighting for each component, thus:-
Paper 1 Writing ... 30 marks > 25%
Paper 2 Receptive skills ... 65 marks > 50%
Oral Interview ... 30 marks > 25%
So... we have to scale the marks mathematically. In two cases, this is simple enough:-
Paper 1 Writing ... divide mark by 6, multiply by 5
Oral Interview ... divide mark by 6, multiply by 5
... but in the case of Paper 2, it is slightly more complicated:-
Paper 2 Listening section ... there are 25 marks, and 25% is allocated for Listening, so do nothing to the mark
Paper 2 Reading section ... there are 40 marks, so these have to be scaled - divide by 8 and multiply by 5...
... then add the two together to give the total out of the 50% allocated for Paper 2
Which is all simple enough, if a bit of a fiddly bore! And remember to round up and round down: the IB only recognises whole numbers, not decimal points or fractions.