The details · Amazon
A fading launch-week rank probably isn't a failing book.
Amazon weights recent sales more heavily.
- From
- Case study · CS-002 · September 28, 2026
How recent activity could affect rank, with other books held constant
An illustration drawn from Amazon's description of rank, not real sales data.
- A one-day spike in sales
- Steady sales
Sources (2)
Source: Amazon: recent activity is weighted more heavily, and rank is relative to other books CS3-124 CS3-139
What I found
Amazon says rank reflects "recent and historical activity, with recent activity weighted more heavily." That's probably why a launch-day burst looks dramatic and then fades.
So do this
Expect the fade. Judge launch week by sales, not by where the rank lands after.
Keep in mind
Amazon doesn't say this is why. It's my reading of how it weights recent sales.
Source: What Amazon actually tells authorsCS3-124
Read the full case studyI read eight Amazon algorithm guides. Here are two top factors, and the short list Amazon actually publishesWhat Amazon tells authors in its own words, what "we modeled it" really means, and the test model I'm building instead.Case study · CS-002 · 8 min read · 9 posts come from it