What's a surge? — A product whose Amazon sales rank suddenly jumps — it's selling far faster than its normal pace (rank at least ~2x better than its recent baseline).

Sustain vs fade — Sustain means the product is still ranking at least ~2x above its pre-surge baseline down the road — still selling at the boosted pace, not slid back to its old rank. Fade = it drifts back toward that old rank. Chase a surge blindly and it usually fades: three months on, only about 1 in 5 is still selling this way.

The edge — When we call a KEEPER, about 1 in 3 are still selling three months on — vs the ~1 in 5 you'd get chasing surges blind. Our strongest calls (the top ULTRA tier) last longest: about half are still going at three months — long enough to source, land, and sell through. The table above shows how those odds slide as your lead time stretches out. DUDS are the opposite call: the ones at the very top of the list (our most confident) fade almost every time. Confidence is why we rank them.

Confidence — How sure we are the call holds — higher means surer, for keepers and duds alike (a 90% dud = we're 90% sure it fades).