Comparability studies about qualification standards generally use demand or candidates' performance as comparators. However, these can be unrepresentative for vocational and new qualifications. Consequently, other comparators need to be used. This article details the process of devising and piloting a research instrument to compare the features of cognate units from diverse qualifications and subjects.

First, knowledge was elicited from twelve experts through Kelly's repertory grid interviews where they were asked to compare different types of qualifications. This data was analysed thematically. Four features and several sub-features were identified. These features were used to categorise the interview data and develop the research instrument. A pilot of the instrument indicated that salient features varied between units. Therefore, the instrument is suitable for use in future comparability studies about features. However, conventions still need to be agreed for how to analyse the data that is collected using the instrument.