About 10 days ago, an architect asked me the difference between a Decorator and a Designer.
A week before I was told by a contractor that one of the best known local "designers" has to take an assistant to every meeting because he can't read blueprints. It's so aggravating, I won't even go there. That's like a dentist who needs an assistant to diagnose the patient.
**If he can do window coverings and pick furniture and pretty colors, he's a decorator until he knows how a building goes together and can read a set of Construction Documents (not the same as a floor plan) -- and ideally draw up what he needs to show his own clients.**
Here's some quick and direct info --MY answer, but I am positive that I would find LOTS of agreement within the REAL Design community including related professionals. Here's a good "Short Version":
How can you tell? ASK!! I have all sorts of minutiae on my business card that says I am IL Registered, NCIDQ Certified. "Interior Planning", "Decorating", "Consulting", etc. on a biz card are NOT the same.
Until sometime in 2009, from about 1993, a person who chose products for finishing interiors, no matter what their experience or training was a "Decorator" and a design professional who had professional schooling, taken a national exam and passed it - or someone who had been practicing for many years as a design professional and could be "grandfathered" in, was called a "Designer". That was loosened up in 2009. Now others can say "Designer".
The exam is given by NCIDQ: The National Council for Interior Design Qualification. It requires passing a written test covering technical understanding of plumbing, construction, electrical, Historical Interiors (yes it matters) and design theory, PLUS there is a practical exam that includes putting together a presentation reflecting knowledge of style, scale, construction and the ability to do that presentation in only a few hours.
NCIDQ IS the national exam recognized everywhere. (Yay Me, I passed it a while ago and I DO remember it!)