Navigating the Amazon Sales Ranking
First, the disclaimers: Since the algorithm Amazon uses togenerate its sales ranking is proprietary, the details containedherein are extrapolated from research and field tests. Theresulting consensus finds Amazon's system to provide marginalsales data at best.
To whit, read Amazon's own definition of its system, slightlyparaphrased from their FAQ: "The Sales Ranking system exhibitshow books are selling. The lower the number, the higher thesales. The calculation is based on sales and is updated eachhour to reflect recent and historical sales of every item sold.We hope you find the Amazon.com Sales Rank interesting!" Thislast sentence seems to indicate Amazon's own perspective on theimportance with which the sales rankings should be viewed.
You're not supposed to find the sales rankings informative orhelpful. You're supposed to find them interesting.
In actuality, the process is somewhat more convoluted than theylet on. Only the top 10,000 books are updated every hour and theranking does not depend upon the actual number of books sold,but rather, on a comparison against the sales figures of theother 9,999 books within that same hour. Simultaneously, atrending calculation is applied to arrive at a computerizedsales trajectory. So, hypothetically, a book that held a rankingof 2,000 at 2pm and 3,000 at 3pm, might hold a 4,000 ranking at4pm, even if it actually sold MORE books between 3-4 than it didbetween 2-3.
Books with rankings between 10,000 and 100,000 are recalculatedonce a day, rather than once an hour. Current projections, aswell as historic sales information play a key role in thesecalculations. In fact, the predictive nature of the Amazonranking system is what makes it possible for a newly-releasedbook to outrank an older established title, even though theactual sales figures for the latter far exceed the former.
Books with rankings over 100,000 are also recalculated every dayand applied with historic sales information and projections,although in the case of these books, history takes a back seat.Sales projections and trending take an active role here, whichis why a book's ranking can leap from 900,000 to 200,000 in thespan of 24 hours or less. Does this mean the book has sold700,000 copies in 24 hours? Absolutely not! What it does mean isthat recent activity (i.e. purchases) for that book is trendinghigher than those 700,000 books it just surpassed. But, don'tget excited just yet; since the activity of those 700,000 otherbooks range from slow to stagnant, one or two orders aresufficient to catapult a ranking.
If a book's ranking breaks into the top 100,000, the saleshistory calculation starts to rear its head, which is why a"phenomenon" book has a hard time maintaining a high, legitimateranking. A phenomenon is defined by a book that leaps from thehigh hundred-thousands into the lower thousands (or better) inthe span of 24 hours or less, usually due to some concentratedmarketing initiatives. Since Amazon's sales history for thattitle doesn't support the leap, the spike occurs and thenquickly drops again.
HOW DOES ALL THIS TRANSLATE TO ACTUAL SALES FIGURES?
Since the data is recalculated every hour and/or every day(depending upon a book's current ranking), it's impossible toget cumulative sales figures, although those figures are appliedto the algorithm during the calculation. No, to get a very roughidea of the actual number of books being sold, the sales rankinghas to be dissected dynamically, with the same immediacy as theranking being calculated, (hourly for top 10,000 books or dailyfor top 100,000 books). Chart the ranking of a top 10,000 bookevery hour for 24 hours and divide by 24 to arrive at itsaverage daily ranking. In the case of a top 100,000 book, takeits ranking every day for 7 days and divide by 7 to arrive atits average weekly ranking.
Bear in mind that this next piece of information is extremelyarbitrary, based upon sales ranking/sales figure comparisons anddata received from third party sources. In other words, it'sprobably completely wrong. But rather than disclaiming thischart until the cows come home, I'll just say this: It isdifficult to make sense of something that doesn't make sense.But it sure is interesting, and now, perhaps, even slightlyhelpful.
If the book's average ranking is: 2,000,000+ Perhaps a singleinventory/consignment copy has been ordered.
1,000,000+ Current trends indicate total sales will most likelybe under 40.
100,000+ Current trends indicate total sales will most likely beunder 200.
10,000+ Estimate between 1 - 10 copies being sold per week.
1,000+ Estimate between 10 - 100 copies being sold per week.
100+ Estimate between 100 - 200 copies being sold per week.
10+ Estimate between 200 - 1000 copies being sold per week.
Under 10 Estimate over 1,000 copies per week
To whit, read Amazon's own definition of its system, slightlyparaphrased from their FAQ: "The Sales Ranking system exhibitshow books are selling. The lower the number, the higher thesales. The calculation is based on sales and is updated eachhour to reflect recent and historical sales of every item sold.We hope you find the Amazon.com Sales Rank interesting!" Thislast sentence seems to indicate Amazon's own perspective on theimportance with which the sales rankings should be viewed.
You're not supposed to find the sales rankings informative orhelpful. You're supposed to find them interesting.
In actuality, the process is somewhat more convoluted than theylet on. Only the top 10,000 books are updated every hour and theranking does not depend upon the actual number of books sold,but rather, on a comparison against the sales figures of theother 9,999 books within that same hour. Simultaneously, atrending calculation is applied to arrive at a computerizedsales trajectory. So, hypothetically, a book that held a rankingof 2,000 at 2pm and 3,000 at 3pm, might hold a 4,000 ranking at4pm, even if it actually sold MORE books between 3-4 than it didbetween 2-3.
Books with rankings between 10,000 and 100,000 are recalculatedonce a day, rather than once an hour. Current projections, aswell as historic sales information play a key role in thesecalculations. In fact, the predictive nature of the Amazonranking system is what makes it possible for a newly-releasedbook to outrank an older established title, even though theactual sales figures for the latter far exceed the former.
Books with rankings over 100,000 are also recalculated every dayand applied with historic sales information and projections,although in the case of these books, history takes a back seat.Sales projections and trending take an active role here, whichis why a book's ranking can leap from 900,000 to 200,000 in thespan of 24 hours or less. Does this mean the book has sold700,000 copies in 24 hours? Absolutely not! What it does mean isthat recent activity (i.e. purchases) for that book is trendinghigher than those 700,000 books it just surpassed. But, don'tget excited just yet; since the activity of those 700,000 otherbooks range from slow to stagnant, one or two orders aresufficient to catapult a ranking.
If a book's ranking breaks into the top 100,000, the saleshistory calculation starts to rear its head, which is why a"phenomenon" book has a hard time maintaining a high, legitimateranking. A phenomenon is defined by a book that leaps from thehigh hundred-thousands into the lower thousands (or better) inthe span of 24 hours or less, usually due to some concentratedmarketing initiatives. Since Amazon's sales history for thattitle doesn't support the leap, the spike occurs and thenquickly drops again.
HOW DOES ALL THIS TRANSLATE TO ACTUAL SALES FIGURES?
Since the data is recalculated every hour and/or every day(depending upon a book's current ranking), it's impossible toget cumulative sales figures, although those figures are appliedto the algorithm during the calculation. No, to get a very roughidea of the actual number of books being sold, the sales rankinghas to be dissected dynamically, with the same immediacy as theranking being calculated, (hourly for top 10,000 books or dailyfor top 100,000 books). Chart the ranking of a top 10,000 bookevery hour for 24 hours and divide by 24 to arrive at itsaverage daily ranking. In the case of a top 100,000 book, takeits ranking every day for 7 days and divide by 7 to arrive atits average weekly ranking.
Bear in mind that this next piece of information is extremelyarbitrary, based upon sales ranking/sales figure comparisons anddata received from third party sources. In other words, it'sprobably completely wrong. But rather than disclaiming thischart until the cows come home, I'll just say this: It isdifficult to make sense of something that doesn't make sense.But it sure is interesting, and now, perhaps, even slightlyhelpful.
If the book's average ranking is: 2,000,000+ Perhaps a singleinventory/consignment copy has been ordered.
1,000,000+ Current trends indicate total sales will most likelybe under 40.
100,000+ Current trends indicate total sales will most likely beunder 200.
10,000+ Estimate between 1 - 10 copies being sold per week.
1,000+ Estimate between 10 - 100 copies being sold per week.
100+ Estimate between 100 - 200 copies being sold per week.
10+ Estimate between 200 - 1000 copies being sold per week.
Under 10 Estimate over 1,000 copies per week
Source...