Can apply to: Books
Metric definition: The number of times a book has been purchased. Sales ranking is a derivative metric that demonstrates how well a book is selling in comparison to other books.
Metric calculation: The number of times a book has been purchased across the data sources being tracked by the metric provider. Sales rank is a relative representation of how a book is selling in comparison to all books or other books in the same subject category.
Data sources: Point of sale data from book retailers.
Appropriate use cases: Book sales and rankings can be used to demonstrate popular attention to a work.
Limitations: Detailed, complete, and historical sales information can be difficult to obtain, as even the most comprehensive are limited to the recent past and do not include sales to libraries or used book sales, for example.
Inappropriate use cases: Monograph sales are not a direct measure of readership, research quality, or impact.
Available metric sources: Authors can access their sales data via Amazon, figures are provided by Nielsen BookScan. Additionally, Amazon sales rank data is available from Sales Rank Express and NovelRank.
Transparency: Book sales data and ranking calculations are often proprietary. Purchaser data is anonymous.
Timeframe: In most cases, historical sales and ranking data is not available, but books of any age may be included.