Comparability between different educational qualifications is an important issue within policy discourse in the UK. In this context, the comparability of qualification demands has been explored through the use of expert human judgement. The involvement of human judgement in estimating assessment demands has consequences for methodology. This review considered the ways that the Kelly's Repertory Grid (KRG) technique has been used to compare assessment demands over recent years. The review involved the identification and analysis of research documents as well as consideration of the original theory on which the KRG method was founded. This article describes how the technique has been adapted as it has shifted from its original psychotherapeutic context to be used in educational assessment and comparability studies. The review also explored possible disadvantages that stem from these adaptations, leading to recommendations to ensure the validity of findings when using the technique in educational assessment studies. (Contains 1 figure.)