At this stage of the two-year IB Diploma course, many teachers are wondering about their students’ final grades, perhaps trying to reconcile what they considered a near-perfect mock exam result and a near-perfect Internal Assessment result with the middley grade that the student eventually received following the actual exam session. Some teachers question their ability to interpret the Subject Guide and the assessment criteria descriptors, but they shouldn’t, especially if they’ve put time and effort into reading and understanding the Guide, attending training workshops and engaging with their MyIB subject community.

During the exam session, the students’ exam scripts are sent to the markers via a scanning centre. The students’ answer papers are scanned and uploaded to the online marking database. Markers, who have received mark schemes and undergone training then access the database and read/mark the exam scripts. They do this quickly to meet deadlines and quotas.
About every 10th exam script is called a ‘seed’; it has already been marked, and the marker’s marks are compared with the existing marks. If the marker’s marks are within an acceptable tolerance range, the marker continues to access the database of exam scripts. If the marker’s marks are too different from the seed’s marks, the marker is diverted for more training, and may return to the database of scripts if/when their marking becomes more accurate/aligned with those of the chief marker (sounds Orwellian, right?)
Each marker is assigned to mark only Paper 1, 2 or 3.
Now the computer takes over. The marker’s marks are moderated to be consistent with the chief marker’s marks. This is an attempt to standardise the marker’s marks through the whole marking session.

A combination of people and computers confirm the mark boundaries. People will pull out papers on the boundaries, read answers and ask if this set of answers is consistent with the Grade 7, 6, 5, etc. descriptors. The computer then adjusts grades to ensure a certain percentage of students achieve a 7, 6, 5… This is called scaling. It can be controversial, especially when assessment is supposedly done with respect to assessment criteria descriptors which are objective and in theory are either achieved or not achieved. Scaling though protects against grade inflation, which can occur when teachers and students learn what is required to achieve a 7 as each set of results occurs, a greater % students achieving the higher grades.
The internal assessment is marked by teachers and the grades for each of the 4 criteria are entered into IBIS. IBIS then selects a sample of high, middle and low scoring IAs and the DPC uploads the digital copy of the selected sample which are then check marked by an experienced and trained/supported moderator. This moderator enters a grade for each criterion and the computer software then adjusts the teacher’s full set of results (not just the sample IAs’ results)… for exam Criterion A marks may be moderated up by a small percentage and Criterion C grades might be moderated downwards by a lot and Criteria B and D may not change. These moderations are applied to a school’s full cohort, pro rata, i.e. taking into account the unmoderated marks awarded by the teacher. It’s an odd procedure based on dubious logic. (It’s really odd when a moderator’s own students’ IA marks are moderated by a different moderator and the marks go down by a lot.)
These moderated marks are then scaled to match an expected % of grades. And yes, that’s also contrary to the philosophy of criteria-based assessment.
There’s a lot to like about this assessment system. Human markers’ grades are checked frequently to ensure they match the chief marker’s standard for each component (Papers 1, 2, 3, and the IA). The papers at the grade boundaries are checked against the grade descriptors. IA moderators’ marks are moderated by senior moderators…, and then the computer applies grade boundary checks and scales marks to meet grade distribution expectations.
And when grades are received students can submit an EUR – an enquiry upon results at several levels… check the component marks were correctly calculated, a re-mark of papers or even the IA which is problematic to understand because a student excluded from the sample may have to find and then submit their IA even if it was not one of the uploaded sample of IAs selected for moderation. That doesn’t bear thinking about for too long though. If the student’s grade (not mark) changes after an EUR the (hefty) fee is refunded, but if not, not, so… that doesn’t bear thinking about for too long either.
The big question that many teachers ask is, ‘Why are the actual grades not as good as the grades I think their students should get?’
- We tend to mark our students higher than real examiners because we tend to give our students ‘benefit of the doubt’ marks.
- Markers are less patient with difficult-to-read handwriting, while teachers come to learn the students’ handwriting.
- Markschemes tend to be written with more detail than the subject guide’s assessment descriptors.
- Teachers sometimes base marking on ‘knowledge’ gathered from unofficial, for-profit subscription-based sites and really unofficial sources such as Facebook groups. Psychology has one FB group that is well known for distributing incorrect information – and now you’ve now been warned!
- Scaling. It’s quite likely that experienced teachers’ marks are similar to the actual marks, but after papers and IAs have been marked/moderated, the marks are scaled so that the grades are distributed as per IB’s grade distribution ‘formula’ for each subject. The difference (and the cause of so much angst) is likely due to the scaling factor.
In the end though, the grades are just one pillar of what students, teachers and schools achieve. In many ways, that final grade can be distorted, for example, which subjects were chosen to construct the student’s Diploma, which subjects were done at HL and SL, was Language B really a student’s second language or a second first language, how much support was given with the IAs, EE, TOK assessments, how much time went into CAS, etc. What we do know is that most IB Diploma students develop critical thinking skills, they develop an appreciation for internationalism and they appreciate the value of creativity, activity and service. And they all develop in alignment worth the Learner Profile to some extent – becoming better communicators, more open-minded, more thoughtful, more caring… and the IB doesn’t scale these (probably). So… don’t stress too much about the number on the results page. Our students and the teachers’ efforts will always be more than that Diploma score.

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