On measure for me is would I want to sing it if I didn't write it? Does it transcend the writer? Does it "have legs"?

Good songs have interesting tunes (sometimes simple but they carry story well), imagery that's fresh, specificity in subject matter helps, a point-of-view that's consistent with the character that's singing or being sung about, well-constructed with scancion (sp?) from stanza to stanza, a subject that is universal in its appeal, one that lasts over time because it has the elements of good writing, in some cases accessible and in some cases not because it requires time for people to catch up to it, sometimes a product of careful editing, a timeliness about it that makes it relevant, is it utile (in a show or express and idea that people want to hear)....other than those qualities much is about subjective opinion.

As to the marriage of words and music by one composer/author that's not as prevalent as it was at one time. There were more Cole Porters in the earlier days

Some of the best songwriting came from the early Renaissance period in Europe (Dowland, Campion etc.), the American Broadway musicals of the 30's through early 70's (so many wrote great songs as a team or as individual composer/lyricists and the "craft" writers from Tin Pan Alley and the movies. The Pop Sixties were interesting too with Joannie Mitchell, Paul Simon, Burt Bachrach and Hal David, some of the Motown writers, Jim Webb, Dylan, Prine, and Christopherson. Some of it came from jazz with Duke Ellington and his protege Billy Strayhorn in the Forties. The Chanson of Jacques Brel and contemporaries were good. Can we include Pete Seeger also? Woody Guthrie for sure.

How do you feel about Steve Earle, John Gorka, Don McClean? I think they qualify.

The areas mentioned above make all of these writers exemplary.

The reason why I bring this up is that if you want to be a good songwriter, you have to do your homework and study the "masters".

Then define what you mean as a "good" songwriter.

Frank Hamilton