Breakers, starving campaigns, data the numbers cannot be trusted on, and any genuine reply still sitting unanswered.

Replies exclude autoresponders. Opens are not tracked and are never shown.

The slice Instantly cannot show. A campaign carries several business types inside one message family, so the campaign average describes nobody. Anything under 200 contacted is directional.

Off a 3% baseline, detecting a five point lift needs about 326 sends per arm. Detecting two points needs 1,506, which is ten working weeks. Arms below the read floor are not results.

Sibling inboxes are a natural control group: same copy, same list, same day. One drifting away from the others is a deliverability signal long before a bounce rate moves.

Pre-registered before the first send, with the stopping rule written down, so nothing gets reinterpreted afterwards into a result somebody wanted.

Launch briefs marked pending. Nothing reaches a real person until one of these is approved.