Most Amazon pricing decisions are still made without measurement.
Media is attributed to the cent. Content is A/B-tested. But where deal funding goes, whether a cost increase gets passed on and how deep a promo cuts are still decided on instinct. This site measures them, one category at a time.
The weak end of the series: price effects exist in both directions, at roughly a fifth of what the strong categories show, in a market that answers in weeks.
cuts 0.19 [0.03 to 0.47] · increases 0.24 [0.08 to 0.42] · reliable
Each weekly report measures a single category. The Monthly is where they get compared. One subscription: The Monthly every month and the Quarterly every three months.