Metrics
What is Engagement Rate?
A composite measure of how recipients interact with your emails, combining opens, clicks, and replies relative to messages delivered.
Engagement rate aggregates positive recipient signals such as opens, clicks, and replies, divided by delivered volume. Mailbox providers track their own engagement signals (reading, replying, moving to a folder, marking not-spam) and weight recent engagement heavily when deciding inbox versus spam placement. Because Apple Mail Privacy Protection and prefetching inflate open counts, clicks and replies are more reliable engagement signals than opens alone.
Why it matters for cold email
Provider algorithms at Gmail and Microsoft place mail based on how engaged your recipients are, so high engagement directly buys inbox placement for cold campaigns. Low engagement, common when targeting cold or stale lists, trains the provider to filter you, which is why pruning unengaged contacts protects the whole sending domain.
Related terms
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