Whenever you run a course where you want the outcome to be a shift in perceptions, attitudes or beliefs (name a course that doesn't) you can use the Repertory Grid Technique (Repgrid) as a pre/post test to measure the extent of the shift. Even if, like me, you are primarily involved in designing and running skill courses where the outcome can be spelled out and observed in behavioural terms, the Repgrid can be used to establish whether underlying attitudes have shifted to align with newly acquired behavioural skills. This article will show you how to use the Repgrid as a way of validating any course. Rather than run the risk of confusing you by chopping and changing between different courses I shall confine my description to how I use the Repgrid to validate one particular course. The course is designed for ICL salesmen with the overall objective of getting them to be more interactively skilled. I shall not bore you with a blow by blow description of the course because it isn't relevant to this article. We only need to highlight the start and finish because that is where the Repgrid is used.