Beta reading provides feedback on the pace, the characters, the setting; anything that impacts on the structure and style of the story is fair game. When I beta read, I’m aiming to give the author an idea of the strengths and weakness of both story and style, and spot any plot holes or major omissions early in the publication stage. If there are no teeth in the story, the author may turn to writing something else. But, usually, for my writers, the suggestions I give are the issues that need addressed before continuing. Many writers have told me the feedback I give is exactly what they needed. Writers become so close to their stories; they need a second set of eyes. That’s when it’s time for a beta read.
What doesn’t get addressed
At a beta read stage I will not advise about sentence structure except to comment on any style issues. Nor will I be picking up on spelling mistakes or punctuation errors, unless to comment on those that are frequent. To the best of the writer’s ability, grammatical mistakes and punctuation errors should be fixed before the MS is sent to beta reader. It is very difficult to focus on the content of the story if a MS littered with mechanical error.