Resource descriptions and the User

Its interesting that at the heart of any system that a library or any information organisation employs is the users themselves. This was driven home in the physical library sense while on the study visit and I can also see how this marries well with the idea of metadata creation  and the physical arrangement of information resources in a library. For what is the point of using a system to describe a resource is it doesn't apply the terms, values or records those attributes that the user will utilise in searching?

http://usabilitygeek.com/wp-content/uploads/2013/05/Requirements-Gathering-User-Experience-UX-Project-Cartoon.jpg