(1) If a biblical book presents a clear structure and literary elegance (e.g. Ruth): "This composition is obviously the product of a long history of redaction during which original traditional material was shaped into the elegant structure we now observe in the final form of the text."
(2) If a biblical book presents an obscure structure or signs of disorganization (e.g. Micah): "This composition is obviously the product of a long history of redaction during with original traditional material was interpolated and supplemented with later additions, thus disrupting the structure and resulting in apparent disorganization."
How about this alternative hypothesis for "untidy" biblical books? "This composition was thrown together overnight from oral tradition and fragments of written oracles by a scribe fleeing for his life from Babylonian soldiers."
Just kidding, of course. : )