I'm always fascinated by bestseller lists and how books get there (because, yeah, I want mine there too).
For the last three weeks, I've had the thrill of seeing my Allyson James pseudonym appear on the New York Times mass market bestseller list at the following ranks: Week 1: 15; Week 2: 14; and Week 3: 35. The first two weeks were printed in the newspaper, and you bet I grabbed a copy of each.
Now, this was for an anthology, and I know that, duh, the lead authors in this book were responsible for it getting on NYT and I was just in the car with them. But it was a thrill, nonetheless to see my name on the coveted print list.
I'm always curious about bestseller lists and how they're put together. And also, who it's important to. As an author, I'm stoked when I get on one. As a reader--I think I can't be paid to care. I read what I like to read, and will think no less of the author or the book if they're not "bestsellers." But publishers get very happy with you when you hit a list, and booksellers start to privilege you, so as a writer, it's in my career best interest to do so.
The USA Today top 150 lists the top 150 sellers for the week, be they nonfiction, fiction, mass market, hardback, YA, romance, self-help, whatever (some things are left out, like category romance). They have handy web page: http://content.usatoday.com/life/books/booksdatabase/default.aspx which lists the current week, plus provides a searchable database, so you can look up "Jennifer Ashley" and "Allyson James" and see me there (all right, if you're not my mother, you don't have to do this).
According to the USA Today page, books are not broken down into formats--for example if a hardcover, mass market, and ebook copy of a book are all available for sale, the sales are counted together.
You can read the whole explanation of how the list is generated and who gives them sales data here: http://www.usatoday.com/life/books/booksdatabase/2006-06-14-bookslist-about_x.htm
The New York Times list, on the other hand, breaks its lists down into categories and formats.
From their handy website: http://www.nytimes.com/pages/books/bestseller/
they have separate lists for:
Trade paperback fiction (those oversize paperbacks that run about $15)
Mass market paperback fiction
Hardcover Advice books
Paperback Advice books
Hardcover Business bestsellers
Paperback business bestsellers
Here is what the page says about how they get the numbers for these lists:
"These lists are an expanded version of those appearing in the November 8 print edition of the Book Review. Rankings reflect sales, for the week ending October 24, at many thousands of venues where a wide range of general interest books are sold nationwide. These include hundreds of independent book retailers (statistically weighted to represent all such outlets); national, regional and local chains; online and multimedia entertainment retailers; university, gift, supermarket, discount department stores and newsstands. An asterisk (*) indicates that a book’s sales are barely distinguishable from those of the book above. A dagger (†) indicates that some bookstores report receiving bulk orders. Among those categories not actively tracked are: perennial sellers; required classroom reading; text, reference and test preparation guides; journals and workbooks; calorie counters; shopping guides; comics and crossword puzzles"
In the publishing world, the New York Times list carries the most prestige. It's a difficult list to crack. In my personal opinion the USA Today list is even harder--you're competing with cookbooks and the most popular YA as well as your fellow romance or mystery authors in all formats. This would explain why people can hit the New York Times extended lists (#21-35) and not make USA Today top 150.
Then there's Bookscan, which most readers never see. I read all over the place that Bookscan represents 75% of all sales. That might be true for hardbacks, but it is NOT for mass market fiction, especially mass market paperback originals. For mm originals, Bookscan represents about 25-30 percent (this is data taken from my own royalty statements; I'm sure mileage varies.)
The main reason for this disparity is Wal-Mart. Wal-Mart does not report sales to Bookscan (at this time), and Wal-Mart sells a gazillion mass market paperbacks. In my own experience, Wal-Mart accounts for the largest chunk of my print runs.
Bookscan is a private list owned by Neilsen, and you need a subscription to view it. If you're in Romance Writers of America or Novelists Inc, you get a chance to look at Bookscan lists at a substantial discount. I like it because when my book makes the top 100 romance list, it gives me a good indication of how my book is getting out into the world. The list shows total sales for each book for the current week, the previous week, and total year to date. It's only a slice of the pie ('cause, Wal-Mart), but it's helpful to get a relative picture.
So there you have the dirt on bestseller lists. As authors, we are constantly judged by them. As a reader, I personally don't care, although I know readers who refuse to read anything not on the New York Times top 10 (I feel so sorry for them *g*).