Measuring Script Writing Competency?

This is a Programmers Competency Matrix. As far as I know there are no such standardized rating systems for GIS scripting, but I might suggest modifying this one - the Programming heading/matrix would be the most relevant and needs little modification to make it relevant to GIS as most of the same principles apply.

The nice thing about a matrix like this is it goes beyond just the syntax/semantics of the script itself - it also looks at the coders' problem solving, communication, and organizational skills; all of which have a huge influence on the end product they are producing.