Reading Inbox Placement Data Without Guessing

It's tempting to treat every deliverability metric as one signal — 'engagement is down, something's wrong' — but bounces, complaints, and opens each point at a different part of the pipeline, and mixing them up leads to fixing the wrong thing.

Bounces: a list problem, not a deliverability problem

Hard bounces mean the address doesn't exist. A rising hard bounce rate is a list hygiene problem, not a deliverability problem — it means addresses have gone stale since they were collected, and continuing to send to them is what actually damages sender reputation over time.

Complaints: the metric that matters most

Complaint rate (recipients hitting 'mark as spam') is the metric mailbox providers weight most heavily, and it's a content and expectation problem more than an infrastructure one. People rarely complain about mail they expected to receive, even if they don't open it — they complain about mail that feels unexpected, too frequent, or irrelevant.

Open rate is the noisiest of the three. Privacy-focused mail clients now prefetch images for many messages regardless of whether a human opened them, which inflates opens without reflecting real engagement. It's still useful directionally, over time, on your own sends — just not as an absolute number to compare across campaigns.

The pipeline order that actually helps: check bounces first (list problem), then complaints (content or targeting problem), then use engagement trends as a slower-moving confirmation rather than a daily read.