How the list is put together
Every drop compares today’s in-stock price against the median price the same store had for that product in the last 14 days. The median — rather than the single highest point — defuses short price spikes that would otherwise masquerade as deeper discounts than they really are.
To make it here a product must be listed at 2+ tracked stores (single-store prices can be scrape glitches), the 14-day window must have at least 4 samples for the same store, and the drop must be at least 5 % — anything shallower is noise. Drops above 40 % are kept only when a second retailer currently prices the same product within 15 % of the deal; drops above 60 % are always suppressed as scrape noise. Amazon is excluded entirely — Amazon Associates rules forbid displaying Amazon price history or price drops.