A year ago, for reasons not relevant here, I decided to record every Kindle ebook uploaded to Amazon for a full month. For the sake of my sanity, I restricted it to epic fantasy. I recorded 390 ebooks uploaded over the month of April 2013, excluding foreign language ones.
A year on, it occurred to me that it might be interesting to see what had happened to those 390 books. So during April 2014, I looked each one up on Amazon, and noted the number of reviews. These are total numbers; I didn’t attempt to track numbers of 5*, 4* and so on. I noted rankings, too, but these are just a snapshot in time, whereas reviews are cumulative.
Ignoring ebooks that have disappeared, there are 338 books with review numbers. Two books are anomalous: Memory of Light has 3,048 reviews, and Blood Song has 1,374. Below those outliers, a Mageborn book has 309, Promise of Blood has 255 and a Casey Odell has 147. A couple of others also have more than 100 reviews. Nobody else comes close.
Here are the overall numbers, of the 338 surviving:
0 reviews: 38%
1 review: 13%
2 reviews: 10%
3 reviews: 4%
4-9 reviews: 14%
10+ reviews: 20%
So 38% of these books have no reviews at all after a year – which is kind of tragic. And 66% have fewer than 4. Just 20% manage double figures.
Here’s the part you could have predicted: the highest ranked books also have the most reviews. Those in the top 5% of ebooks (rankings 1-125,000) have an average of 165 reviews (or 42, if you exclude the two outliers). After that the numbers drop off precipitously.
Impossible to say whether a large number of reviews lead to higher sales, or whether high sales result in more reviews, but there does seem to be a correlation. However, as you might expect, there are big exceptions: some high ranked books have very few reviews, while some with a lot do poorly.
None of this is particularly startling. The only aspect that surprised me was how many books had very few reviews, or even none at all, after being on sale for a full year. That does suggest that a lot of them are just not selling and/or not being promoted. And the take-home message is the obvious one: promote and get reviews.