I sent Coincidence to 4 individuals who volunteered to be beta readers. 3 are writers, two primarily fiction and one mainly poetry. If I recall the original email correctly, I said I simply ask if they like it, with the caveat that if they could not finish it, they tell me (for instance, if it was so terrible they had to put it down). Any editing or suggestions beyond that would be their decision.
From my understanding, it takes some trial and error to figure out exactly what you expect from a beta reader. But the way I looked at it, I see beta readers as I would a professional editor (despite not using one for this project). I’ve edited a few documents, including 3 novels for 2 authors, and I know how I like to receive a novel: complete. The one author gave me a Word doc filled with 20+ beta readers’ tracked changes and a print copy with another reader’s illegible notes.
Now, the strangest part about this was that none of these notes or changes were actually made. Maybe it’s me, but I expect the editor to “master” (in audio terms) the “track.” Maybe some commas need to be removed or some details need to be expanded or rearranged. An entire character should not be told to be removed. This is poor writing. If the author is all right with the character and the character passed the beta readers, then he or she is probably ready for an editor.
By the time it reaches the beta readers, the story should be complete in the writer’s eyes. You wouldn’t hand an editor your scribblers on a bar napkin, so why give your beta readers anything less than a full tale? The expectation, to me, is to ensure the less obvious parts of the story get across. As Mur Lafferty likes to point out, you couldn’t (or at least shouldn’t) fight with a reader over whether a theme gets across.
The point is that no matter how well-trained you are with the English language and/or human psychology, you just can’t know whether your subtle choices will get across to the reader unless you test them on a set of selected lab rats first. How else would we ever find out whether the final chapter germinates within the reader’s mind?