It is widely accepted that conceptual errors in the early stages of a software process are often the most pernicious. This is because they reflect a misunderstanding of the domain of application, hence we can have a conceptual error in a description which ``looks good'' from an abstract mathematical point of view. A section of the Knowledge Based Systems community is now beginning to forge agreements on the use of terminology for particular domains. Amongst the more formal of these is the Process Interchange Format. The existence of these formal agreements allows limited forms of checking for conceptual errors as a supplement to the normal testing process. This paper describes a method for performing such checks.