Research and analysis

Investigating inter-board comparability of GCSEs

Using step functioning analysis and Rasch modelling to compare GCSE exam standards between exam boards.


Using differential step functioning analysis and Rasch modelling to investigate inter-board comparability of examination standards in GCSE

This file may not be suitable for users of assistive technology. Request an accessible format.

If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email Please tell us what format you need. It will help us if you say what assistive technology you use.


Data were analysed from 16 GCSE exams administered in 2015 by the 4 exam boards that provide general qualifications in England. We investigated the comparability of standards at specific grades in the exams between the exam boards.

The main findings include:

  • higher grades were shown to be generally more comparable than the lower grades in terms of difficulty or standards between the exam board
  • the relative grade difficulties were broadly consistent
  • changes in grade outcomes after aligning standards were moderately or highly correlated with those estimated using the existing inter-board statistical screening procedure with mean GCSE score
  • the use of Rasch ability as a performance measure with the existing inter-board screening procedure produced results which were closely similar to those obtained using mean GCSE score
Published 25 November 2016