When open rate drops, the first instinct is usually creative: rewrite the subject line, test send times, change the preview text.
Sometimes that is right. But sometimes the issue is lower down the stack.
Three common hidden causes
1. The list is weaker than it looks
If the audience includes stale or bad addresses, your results are being measured against a noisier denominator than you think.
2. Deliverability slipped
If more messages are landing in spam or lower-visibility inbox placements, even good subject lines struggle.
3. Too much of the list is disengaged
If large portions of the audience have not interacted in months, open rate will sag even if the email itself is fine.
The practical fix
Before reworking the creative, check:
- when the list was last cleaned
- whether bounce trends have worsened
- how much of the audience is actually still engaged
MailCull helps with the first part by removing obvious bad addresses before the next campaign.