How this need is measured

What we compare. For each pair of products in this audience, we count the visits that viewed both and compare that with how many would have viewed both by chance, given how often each product is viewed and how many products each visit views. A pair counts when at least 5 visits viewed both and that count is at least twice what chance would give, with a small allowance so a handful of visits cannot carry it.

Product types. A product's type is the one your catalog gives it. Open-box and B-stock listings count as the product they are a copy of. Only pairs from two different product types count toward the need.

Over time. We split the window at its middle visit and check the pairings in each half.

Orders. We compare how often this audience's visits end in an order with your other visits, once both have enough orders for a twofold difference to show.

Visits. Each visit follows one anonymous browser. Lantern can't tell who made it.