I rate memoirs the same way that I rate other books. But that doesn’t really answer the question, so here is a very loose description of my rating system:
One Star. I reserve single-star ratings for books that I abandon. It took me a long time to learn to abandon a bad book. Now you get 50 pages. If the story hasn’t captured my attention by then, I abandon the book. There are way too many wonderful books out there to waste my time with one that just isn’t resonating with me.
Two Stars. Two stars means that I finished the book, but don’t feel the need to keep it on my bookshelves. These books are donated to the library book sale. Sometimes I regret reading the entire book, other times, the book was perfectly fine but not something on want on my bookshelf or, if I’m honest, in any of the many piles around my apartment!
Three Stars. These books are staying on my bookshelf, at least for now. This basically means that I enjoyed the book. Either I consider it to be an important work or it in some way reflects who I am or what I believe or what I hope to be. I have a small number of you-should-like-this-because-its-a-classic books in this category, but I’ve been steadily weeding them out. It may be widely considered important or good literature, but unless I consider it important or just really good, it’s out the door!
Four Stars. A book that gets four stars is a book that I truly enjoyed. Sometimes I enjoy the book for its escape value, other times its because I learned something. In all cases, these books have a good story. In my experience, not all great stories are accompanied by great writing. Story is the priority for me. A great story will get a four star review. Amazing writing, with a mediocre story, will get a three star review.
Five Stars. I want every single person I have ever met to read this book right now and then come over so we can talk about it. At length.
What is interesting, is that my ratings change over time. A book that I absolutely loved without reservation two years ago, may not resonate with me as much today. Obviously the book didn’t change, but I am not in the same place as I was when I first read it.