It all started with a tweet from a young editor (who gave me permission to use their tweet, but I’ve decided not to put their name out in public) who said “A developmental editor is not the same as a copy editor is not the same as a line editor is not the same as a proofreader is not the same as a beta reader.” Then, parenthetically, they said editors would be horrified by that run-on.
Except it’s not one. It’s a perfectly grammatical sentence.
I checked with Lisa McLendon (@MadamGrammar) to see if I was on the right track. I was, but my diagramming skills are a little rusty. I left out “the same as” for convenience; that doesn’t affect the grammaticality of the overall structure one whit.
Here’s the quick diagram she sent me:
The fleshed-out version of the sentence in question goes like this: “Developmental editing is not the same as copy editing which is not the same as line editing which is not the same as …” I’m sure you get the idea. Should there be commas before every instance of which? That depends largely on the register (c’mon, you knew I’d go there) of the piece. For my blog here, and for a tweet, commas are largely unnecessary; it’s part of internet register, and it’s fitting for the “front-porch chat” feel I aim for here at my blog home. If we were to hear someone say that sentence, chances are probably 50/50 there’d be pauses. Me? I’d run it all right into one big thought. “This is not that is not that other thing is not that thing way over there.”
If that sentence was used in a text, say, for a 101 editing class, you bet I’d put commas where you’d expect to see them. “Developmental editing is not the same as copy editing, which is not the same as line editing, which is not the same …”
Register drives everything from word choice to style choice to mechanics. And, with or without those commas, this isn’t a run-on sentence.
That’s the heart of the matter, here.