It is sometimes difficult to distinguish between the three terms, but I think I have come up with a pretty decent definition of each term that makes sense. It is not that these definitions are set in concrete and can never be challenged. They can and should be challenged, and likely will be over the years.
An innovative design is NOT original. It is one where someone has taken a known design, say a pattern (I have even seen this done on kits) and has given it his or her own touch. It might be that the person adds some new design elements, such as putting in a cat or some butterflies where there were just flowers before, or perhaps takes a simple 9-patch or other patch design and puts a vase with flowers over the top, or perhaps the person stretches the blocks or otherwise changes their overall measurements, or curves lines that were straight. Some good examples of this type of quilts would be Metamorphosis or some of the New from Old challenges that have been held for years by the AQS.
Above: Nine Patch Revisited by Christine Predd
Again, sometimes it is truly a fine line between the original and the innovative and I think overall we can consider it original if more than 50% IS in fact original in concept.
A derivative design can sometimes be confused with the idea of innovative, but there is a difference. A derivative design is usually a class quilt and is clearly recognizable as the teacher's style. Michael James and Pamela Allen's styles have probably had more derivative quilt designs coming from them than most teachers, though I have seen plenty of others. The thing is that a derivative quilt needs to acknowledge its source. I have seen people entering such quilts and calling them their own designs, and even winning ribbons for them or prize money, and somehow that doesn't quite seem right - not that they shouldn't get a prize, but the fact that they are not giving credit where credit is due.
I think it is very important for quilters, even traditional quilters, to start to learn the differences between what is a pattern, what is innovative, and what is original. Back in the 80s, it was easy to understand the confusion as these things really weren't so clearly delineated, but we have come a long way, and it is good for folks to learn the differences. I think overall it will help to make a lot of folks feel easier knowing that they are getting credit where credit is due.
Right: David Bowie by Anne Copeland from Leslie Gabrielse class