I've actually been getting a bit into beta reading lately, mainly because I want to gain experience as a beta reader for the work of others and also have beta readers for my work, once it is ready for that stage.
My understanding of what beta reading is about is that it's about having other pairs of eyes read your work in its entirety and give you their thoughts and feedback based on the work as a whole. They are not editors who are doing a line-editing or heavy editing (my personal belief is that this is the work for publishing house editors or freelance editors, if you're going the route of self-publishing, which I am). But they give you a chance to expose your work to readers and get overall impressions and feedback on it. They are taking precious time out of their lives and putting effort into giving you some feedback, which we all know takes a lot from people, even if they're just giving you a few comments. Because of this, my belief is that the work I give to beta readers should be as complete as I can make it. It should be a completed manuscript that has at least gone some through some revisions. Ideally, it should be almost ready for publication when it gets to the beta reading stage.
However, I'm starting to see that many writers don't see it that way. They see beta readers as helping them with the writing process and they give them unfinished manuscripts with notes and bits and pieces and expect the beta readers to help shape the work for them. I am strongly against this.
I recently had someone ask me to be a beta reader for their novel. I expected to get a complete manuscript that had at least gone through some revisions (at least one). What I got instead was a train wreck - some completed chapters but a lot of bits and pieces of dialogue and description and lots and lots of notes on scenes.
I did the best I could for the writer, but I couldn't help but think that this writer wasn't very respectful of my time or effort if he/she was expecting me to do part of the creative work for them.
Another writer, in a discussion on this topic, stated that he always sends his unfinished work to beta readers because what's the point of sending them the complete manuscript if he's only going to have to make changes to it after their comments? That made absolutely no sense to me. Isn't the point of beta readers to give feedback on the way the story flows organically and how they feel about the characters and storyline and other elements? You're a writer - you're supposed to do revision, both on your own and based on feedback.
Sorry if I sound like I have strong opinions about this. But I just don't think it's fair to subject people who have agreed to take their time and put their efforts into helping you with your book until you have a manuscript that is as complete as you can make it.
Djuna