Bert...yep..I am writing up my analysis..."fools rush in"..it will not be short & simple, because it won't be designed as a 'definition', but rather as an approach which tries to clarify issues...

Jon W...sure..in line with what I said above, the Blues IS a special case...if I end up with 18....or 27 characteristics which 'tend' to describe folk/trad music, many Blues songs may not have all 27...and not every Blues song will have the same 19 or 23..just as not every ballad will share the same set of defining characters.
I am going to have to work hard to explain my list and to keep everyone from jumping on it as if I meant it to be exact and inclusive. My college major was in Philosophy, and the problem of precise definition is a major issue which I do not take lightly...so this will take me awhile to explain...even to myself. But you know how it is with a 'labor of love' :-)