Regional Development Impacts - what is this

When I was talking to my business geography professor as I asked him to write me a recommendation letter for an urban planning program, he started talking about these "urban planners" he knew that wrote "Regional Development Impacts" or RDIs. I think what he said these were basically assessments written in response to a development plan that indicated how compatible the plan was with concurrency laws and things like that. And he said that these people who wrote the RDIs made a lot of money, which may have piqued my interest most of all :)

So based on this somewhat hazy idea, could any of you fill in the gaps here, if this is indeed something real? Is this pretty much what an RDI is? Do the planners that write them indeed make substantial salaries? Who employs them? What kind of preparation and education do you need for this kind of work? etc.

Anyway, I hope something here has a basis in reality. Thanks!