Normal distribution of academic results – ensuring integrity
Author: Emeritus Professor Greg Whateley
March 2025
‘The process of standardisation adjusts the raw mark so that students are not advantaged or disadvantaged based on the trimester/semester/year they sit the assessment or by their subject choice. After standardisation the distribution of marks is the same from year to year and subject to subject – this is the ideal consistency’.
In truth it is a fair and appropriate process. It is often referred to as normalisation (normal distribution) and/or moderation.
Worth reading - Understanding standardisation in the assessment of student performance | Educational Quality & Assessment Programme | Pacific Community (SPC)
In the Higher Education context
Many (if not most) Universities and HEPs use the process – that is following ‘the bell curve’. The standard curve is best captured -
The underlying rationale being consistency and fairness – over a sustained period.
Worth reading - Bell Shaped Curve: Normal Distribution In Statistics
Worth reading - "Grading on a Curve" and How It Affects Students - Through Education
A recent industry wide exercise (involving 13 HEPs) demonstrates the diversity of grading –
Several outliers (AGE, HEPPQN07, HEPPQN11 and HEPPQN12) demonstrate the inconsistency of non-moderated outcomes.
The following table captures the overall distribution of this project –
The distinction/credit/pass grades are inconsistent in truth – and could be adjusted appropriately.
A fairer and more consistent standardising would tidy up the issue – and I suspect the standardisation of the four outliers would go close to securing a standard ‘bell curve’ outcome.
Consistency and integrity are the keys
In order to maintain consistency and at the same time ensure fairness the use of standardising is critical. The so called ‘bell curve’ (given its shape – and sometimes referred to as Gaussian or deMoivre distribution) in fact is fair and consistent and is readily achieved once the full complement of results has been gathered.
The process is simply about adjusting the results to avoid outliers and maintain consistency. What does occur – over time – is that teaching staff become more realistic and consistent with their ongoing marking – and end up marking to the curve – that is becoming more consistent and fairer in their assessments.
The use of normal distribution also safeguards against challenges to academic integrity. The process ensures integrity throughout the assessment phase and ensures any form of favouritism or bias is avoided - at all times.
Emeritus Professor Greg Whateley is Chair of the Invigilator Plus Advisory Board.
