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What do IB Diploma Programme grades mean?

By Dr Matt Glanville
College Student Taking a Test

Following the publication of IB exam results for Diploma Programme (DP) or Career-related (CP) students following the May 2016 session, it is worth focusing for a moment on what those results actually mean.

In most DP courses the IB uses a seven point grading system, helpfully labelled 1 to 7, where 1 means that the student has shown very little knowledge and understanding in their answers and 7 showing that the student has gained a great depth of knowledge and understanding. These grade descriptors are a core part of how grade boundaries are set. In the core subjects we use grades A to E but the principle remains, each grade means something.

It is difficult to put every single candidate into just one of seven boxes for each course. Students are complex in their understanding of topics and so trying to award one grade is a huge simplification. There will be many cases where a candidate’s performance could be reasonably described by either grade. This problem does not go away if we increase the number of grades to 14 or 28, in fact the issue becomes more common because the more grades you have the more opportunities there are to fall between two of them.

But what does this all mean for candidate results? We appreciate that not every student who scores, for example, 73 marks will have the same understanding of their subjects. Sometimes candidates lose marks because they make mistakes on questions they would have otherwise got right. At other times candidates deserve marks for what they have written but it may represent a deep understanding in one specific topic rather than the subject in general (as indicated by their answers to other questions). When we are setting grade boundaries we will review some candidate work on 73 marks that the examiners judge to be at the lower end of a grade 7 and other candidates’ work which has the same mark but the examiners judge to be at the very top of a grade 6. We make the fairest decision we can so that the majority of students on that particular mark get the grade that best fits their performance.

Most importantly, for these ‘boundary candidates’ both grades are fair based on their performance in the examinations. The problem with putting students into ‘grade-shaped boxes’ is that a one point difference can change their grade. There will always be a candidate one mark away from getting a better grade where ever the grade boundary is set.

Realistically, it would have been fair to award candidates who are one or two points above the set grade boundary the lower grade, and it would most likely be fair to award candidates who are one or two points below the set grade boundary the higher grade – however the important point to note is that in each of these cases both grades are fair reflections of the candidates performance.

So with an element of ambiguity, one might ask if it is reasonable to give out grades at all. Should we simply give a description of the strengths and weakness of the student?  We would strongly argue that this would be even less fair because decisions on a student’s future will be made. If not on ’grades’ then on criteria which are even less fair – how well they get on with an interviewer, how smartly they dress or where they live perhaps?  When assessing IB students, we take great care  in giving a fair and meaningful indication of a student’s performance in their examinations, and whatever the challenges, it is a better measure than trusting completely to other admissions and recruitment departments, who have less knowledge of the student and may take less care when making decisions on a student’s future.


Dr Matt Glanville is the Head of Assessment Principles and Practice at the International Baccalaureate