What is a validated model?

Within computational electromagnetics, the question of what makes a validated model is one which is taking on an ever-increasing importance. Traditionally, computational techniques were used by the few, typically in research environments but are now becoming used by the many - especially in the field of EMC design. This paper attempts to address the question of what makes a validated model from the points of view of both the code developers and also the users of computational techniques in the ´real-world´.