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If you’re an author or aim to be one, you need to understand a strange force which can affect your writing career: Nielsen BookScan.

BookScan tracks the sales of print books in the United States, relying on voluntary reporting of sales numbers by Amazon, Barnes & Noble, and other booksellers. BookScan was launched in 2001 by Nielsen, best known for their data tracking on TV ratings and tracking music sales through SoundScan. Prior to BookScan only publishers had specific numbers on their own book sales and they rarely released this information to the public.

Why does BookScan matter to authors? Because publishers and agents use these numbers to determinate your future potential as an author. If an author tries to land a new agent or publisher, the first thing these people will do is check that author’s BookScan numbers. Low reported sales numbers definitely hurt an author’s career. 

This happened with science fiction author John G. Hemry, who wrote the bestselling space opera series The Lost Fleet under the pen name Jack Campbell. Hemry used this pen name because his earlier series hadn’t sold well enough, raising fears bookstores wouldn’t order many copies of the first book in his new Lost Fleet series. While bookstores don’t use BookScan, instead relying on their own internal sales numbers for purchase determinations, their sales number reporting process is somewhat similar to how BookScan works.

Hemry instead used a pen name for his new series to prevent the poor sales tracked under his own name from causing low pre-orders by bookstores. When The Lost Fleet became a hit he kept using the pen name.

What Does BookScan Track and Not Track

BookScan only tracks trade print book sales in the United States. BookScan claims to track 85 percent of print book retail sales but that percentage does not appear to be accurate. Instead, I have seen many estimates that BookScan captures between 45% and 60% of trade print book sales.

And BookScan doesn’t track the following types of book sales:

• E-book sales (meaning if your book is a Kindle bestseller that won’t be reflected in your BookScan numbers)
• Sales to libraries
• Direct publisher sales
• Direct sales by authors
• Sales at conventions or non-bookstore events
• Book sales outside the United States
• Sales at the many independent book stores which don’t report their numbers to BookScan.

In addition, some types of print book sales are vastly underreported in BookScan, such as with graphic novels and comics. For example, back in 2013 Colleen Doran, author of A Distant Soil, reported that her BookScan numbers were off by 93% of her actual sales. The reason for this is much of the graphic novel and comic trade is sold outside traditional bookstores, meaning BookScan can’t track these sales.

Testing the BookScan Sales Estimate

So how accurate is that 45 to 60% estimate for the percentage of print book sales captured by BookScan?

As part of my recent reporting on the issues with Canadian publisher ChiZine, I examined ChiZine’s BookScan sales numbers (PDF download). These numbers were pulled from the BookScan system on November 12, 2019.

I heard complaints from many authors that these reports didn’t reflect the actual sales on their ChiZine royalty statements. But it wasn’t that the BookScan numbers were wrong; instead, BookScan simply doesn’t track many aspects of an author’s total book sales. 

For example, ChiZine is a Canadian publisher and BookScan doesn’t track print book sales in that country (Booknet Canada is the source for Canadian sales figures). Since ChiZine sold around half of its print books in Canada, those numbers aren’t in BookScan. In addition, ChiZine had significant e-book sales for many titles in recent years, which also wasn’t reflected in the BookScan numbers.

That said, ChiZine still sold about half their print books in the United States, so these sales are tracked by BookScan. And thanks to a number of ChiZine authors who shared their royalty statements with me after my original report, I can now determine what percentage of their United States sales were actually captured by BookScan.

Based on my analysis, it appears BookScan captured about 50% of U.S. trade book sales for the ChiZine authors I analyzed.

I’m keeping these authors anonymous either at their request or on the off chance that revealing these sales numbers could hurt their careers. In addition, not all the royalty statements I saw could be analyzed against the BookScan numbers because in a few cases the ChiZine statements combined the United States and Canadian print book sales (called “returnable retail” on the statements).

However, there were also a number of ChiZine statements where the returnable retail print sales were broken down specifically for the United States. Comparing these publisher-reported sales with their corresponding BookScan numbers revealed that BookScan captured a range of total print sales, from a high of 89% for one author to a low of 20% for another. Most of the statements I analyzed grouped around 45%.

Because of this, I believe the estimates I’d previously seen about BookScan capturing between 45% to 60% of print sales in the USA are accurate, although it’s possible the 60% figure is too high and the range should instead be estimated as between 45% and 50%.

How Authors Should Use BookScan

If you’re an author, be aware of the limitations in what BookScan captures. A good publisher or agent will know BookScan numbers are useful for analyzing overall sales trends but do not reflect total sales. Be sure to point out your correct sales numbers when approaching publishers and agents. 

You can also try pointing out any important sales not captured by BookScan, such as with e-books. If you’ve hit a Kindle Bestseller list, definitely mention that because it won’t be reflected in BookScan. If you’ve likewise sold a large number of books at conventions and other appearances, mention that.

And if you’re an author where BookScan captures a much lower percentage of your print sales than the 45 to 50% mentioned above, point that out. The BookScan numbers for one of the ChiZine authors represented only 20% of their total print sales in the USA. If I was this author I’d mention that to any publisher or agent I worked with. Otherwise people may assume your sales are extremely low when they aren’t.

And if you’re a new author, the good news is you don’t have to worry about BookScan until your first book is published. After that, let the worrying begin.