In determining which stanzas or lines to choose, when choice was possible, he was guided by his antiquarian knowledge and by the general principle of selecting the most poetic rendering among those at his command.

This was his way of showing his respect for the minstrel bards of whom he was fond of considering himself a successor.
So far it is perfectly easy to take his point of view.

But it is more difficult to reconcile his practice with his professions.

We find this declaration in the forefront of the book: "No liberties have been taken either with the recited or written copies of these ballads, farther than that, where they disagreed, which is by no means unusual, the editor, in justice to the author, has uniformly preserved what seemed to him the best or most poetical rendering of the passage....

Some arrangement was also occasionally necessary to recover the rhyme, which was often, by the ignorance of the reciters, transposed or thrown into the middle of the line.