I've been trying to figure out how many copies need to be sold until someone will finally review one of my works. My latest story, The Ghost Ship of Phobos, has sold more copies than my previous works, yet no one has reviewed it. I've always assumed that the percentage was 10% of purchasers who give reviews. Is the percentage lower than that?
How many readers review your book sometimes depends on what type of genre you write in. However, my experience is that extremely few readers leave reviews.
Now I have a question for you: I was wondering where you got the idea to use the name Phobos. Nothing wrong with it, it's just that I have two very old PC games entitled
"Leather goddesses of Phobos 1 & 2" by Steve Meretzky. In his adventure games there was a Planet named Phobos that was ruled by beautiful women!
IF I THOUGHT that your eBook was along the lines of those games I would purchase it now! They were really fun to play!
I started out writing reviews of books I downloaded and enjoyed it, but found myself reluctant to criticize others. Then I received coy little suggestions that I follow some outlines on how to do reviews and I quit. I am an indie publisher after all and the whole idea is to write as I choose, not by others recommendations
Reviews, as near as I can tell, show up randomly. I have a series where the whole series sells well, but the first book in it has far more reviews than any of the other volumes. The next to the last in the series has no reviews at all from its 4 years as an ebook (it does have some from its earlier, paperback days).
Another book, a standalone, was downloaded 1000 times when I tried a Select giveaway (3 years ago) and even made it to #9 in Free Fantasy. It got no reviews at all. It's since gotten one review from someone who had read it years ago, in its paperback incarnation, and apparently decided he needed to warn people who enjoyed my series against buying this one.
Obviously if one sells thousands one will get more reviews than if one sells ten, but there's no clear relationship. It really depends on your audience--did they love it (or hate it) so much they just couldn't contain themselves? Are they the kind of person who enjoys blurbing out their reactions to things? Shy, thoughtful people who thought your book was "pretty good" may never post a review even if they buy everything you ever write.
I think that for books generally it's about 1 percent. For e-books, probably less, and as others have suggested, probably a lot less in the case of freebies. People who get stuff for nothing don't value it very highly and are unlikely to invest the extra "cost" of writing a review.
The Life-Changing Art of Tidying Up (or some such title) has 1,000 reviews and has sold 2,000,000 copies. That should give you some idea!
It sure would be nice if people who read and enjoyed the book reviewed it. For some reason my readership is devoted to the negative, usually because the book fails to meet a cherished standard they have. I put a new twist on a well-known person's life--how dare I?? Meanwhile, the book is still selling, I got a solid, positive review from a blogger and life goes on.
Whenever I buy a product, I look at the overall rating and then read the negative reviews. I will read positive reviews as well, but unless I don't know the merits of the product I am buying already, I will usually not put much weight behind positive reviews. A review that tells me what I already know is worthless, and a review that tells me what someone feels about something is worthless too. Unless, of course, there is an overwhelming number of reviews talking about one thing, good or bad.
The overall rating gives a sense of what readers think of the book, and the negative reviews give me an idea of what to watch out for. If their complaints aren't things I care about, I will still buy it even if the overall rating is low. But if the reviews all point out something I really dislike, even if the book is rated high overall I will probably pass. This goes for just about any product.
I really don't care what the people who enjoyed it think, it's the people who didn't enjoy it that will give me the insight.
Silence is deadly, isn't it? I write different kinds of books. My non-fiction books get reviews but my novels seem to get reviews only on Goodreads and that's when I have a giveaway. When readers buy your stories and they don't say anything, it's like cooking dinner and having your guests remain silent. It's good manners to say, "That was delicious."
Publishing is different. The readers do not "know" you, and many people don't have the time to leave reviews. The reward is in the sales. Obviously people like them or they would have returned them.
That's my favorite aspect of Goodreads. I have had probably over 50% of the winners of my giveaways, review the books. It is a good litmus test.