In December of last year, I issued a challenge (really to myself) to work on a 'service oriented coupling index'. I was searching for a quantitative way of determining how loose or tightly coupled software entities are. I took a look at much of the academic literature but found that most of it was out of date or needed rethinking in the service oriented world. More recent work, such as that performed by Doug Kaye was a great help in the pursuit.
At the end, I produced an initial report called, "An Inter-Service Coupling Index for Lossless Exchanges"
I learned a couple of lessons in the process:
1. A coupling index is possible, however the quantitative aspect still lies in the eye of the beholder (which Doug and others warned be about). Thus, in many ways the coupling index becomes a 'best practices' in coupling guide.
2. The pursuit of the coupling index was extremely interesting. I am convinced that the value to be taken away from the report isn't the index but rather the insight on areas where coupling may still be reduced.
Please feel free to send me your thoughts (good or bad). I plan on putting out an updated version on Jan 1. And thanks again to all of you who sent me early feedback. Have Fun! jeff