Wednesday, 20 August 2025

Why grade boundaries can be misleading

In advance of the release of figures for GCSE tomorrow and to avoid wasting time and drawing misleading conclusions, it’s important to understand the relationship between raw marks and grades and how grade boundaries fit into this.  The principles apply to both GCSE and A Level.

Ofqual have released helpful posts to explain the situation to candidates.  I have copied and pasted these at the foot of this post.

 Ofqual on grade boundaries (in 2024)

https://www.gov.uk/government/news/guide-to-as-and-a-level-results-for-england-summer-2024

Ofqual 2025

https://www.gov.uk/government/publications/gcse-and-a-level-grading-what-you-need-to-know/gcse-and-a-level-grading-what-you-need-to-know

 Therefore

(1)   Don’t look at grade boundaries in other subjects or in other languages

(2)   As far as any individual subject is concerned, because the national % getting each grade remains essentially constant, any change in grade boundaries will be a reflection of whether the pupils score more or fewer marks in the papers than in other years.

 It is tempting to want to talk about something which seems tangible (figures) but it can be  unhelpful when in fact the raw marks and boundaries do not tell you anything about standards from year to year,  from subject to subject , or paper to paper.

Copy and paste of Ofqual messages:

Ofqual on grade boundaries (in 2024)

https://www.gov.uk/government/news/guide-to-as-and-a-level-results-for-england-summer-2024

Ofqual has said: “Exam boards have set grade boundaries this summer based on a combination of data and qualitative evidence. As in any year, there has been an important role for examiner judgement. Expert examiners have reviewed the quality of students’ work compared with previous years.

 Grade boundaries typically change each exam series and are often different between exam boards. This reflects any differences in the difficulty of the assessments. If an exam paper is harder the grade boundaries will be lower, and if an exam paper is easier the grade boundaries will be higher. This is important to ensure that students are not advantaged or disadvantaged based on the exam paper that they sit. This means that some grade boundaries are lower than 2023, while others are higher.

 Grading has taken place as normal this summer and standards have been maintained from summer 2023. Students can therefore be confident in the grades they receive, irrespective of the grade boundaries or how they compare to last year.”

 [my summary] In practice, the process of maintaining similar percentages getting each grade in each subject (subject to entry profile changes) has been in operation for nearly 15 years and is referred to as “comparable outcomes”

 Ofqual 2025

https://www.gov.uk/government/publications/gcse-and-a-level-grading-what-you-need-to-know/gcse-and-a-level-grading-what-you-need-to-know

Grade boundaries change from year to year 

If an exam is easier than in previous years, the grade boundaries for that paper will be higher. If it is harder, the grade boundaries will be lower. 

The difficulty of exam questions varies year to year, even though exam boards try to keep the level of demand consistent. That’s because it is impossible to determine how difficult students will find a paper until it is taken. 

This is why new grade boundaries are set each year – to reflect the difficulty of that particular paper, and to ensure that it is no easier or harder to get a grade in any given year.  

The standard of work needed to get each grade remains comparable year on year 

The quality of a student’s work in their exams determines the grade they get and no-one is advantaged or disadvantaged by the year in which they happen to sit the exam​. There are no quotas for the number of students who must pass or fail a subject each year, and no cap on the number of students that can get each grade.  

The fact the number of top grades awarded is relatively stable from year to year reflects the fact that student performance is typically relatively stable too. ​ 

Grade boundaries are set with the aim of maintaining standards over time, not to ensure that the same proportion of students get a particular grade. 

Grade boundaries are decided after students take exams and when marking is nearly complete 

Exam boards set grade boundaries by analysing data about the students taking the qualification and comparing it with those that have taken it previously. This data is used to identify potential grade boundaries, which reflect whether students found the exam slightly harder or easier than the previous year.  

Senior examiners then scrutinise samples of work from students who have achieved marks on and around these potential grade boundaries. This is compared with work of students from the previous year who were on the same grade boundaries.  

Those scripts are studied to determine if the standard of work at the potential grade boundary is appropriate. Senior examiners use the evidence from their scrutiny in combination with the data, to recommend final grade boundaries. 

The number of students achieving each grade can differ between exam boards offering the same qualification 

Grade boundaries typically differ between exam boards, because grading reflects the level of difficulty of each particular paper. All exam boards must cover the same subject content and assessment objectives, and follow the same rules. But there are often small differences between the type of questions they ask or the balance of different types of questions in a particular paper. 

Similarly, while exam boards try to keep levels of demand consistent year-on-year, this is also very difficult to do in practice.  

Where grade boundaries increase between one year and the next, or are higher with one board than another, it does not mean it is more difficult to achieve a grade. Rather, it reflects that that exam paper was easier. Equally, where grade boundaries are lower with one exam board than another that reflects that the paper was harder, not that it is easier to get a particular grade. 

 

 

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