Open rates dropped: what to investigate first
Photo: Avila Ops Tecnologia
When open rates fall between sends to the same list, delivery is more likely than copy: some emails went to spam. Investigate delivery, list, subject, timing and tool in order. Each step eliminates one cause in under five minutes. Only change subjects after ruling out delivery.
The temptation is the opposite: rewrite the subject and resend to the same list with the same problem. First remember what opens measure and do not measure: What open rates do not tell you.
What changes between sends can reduce opens?
A fall from 40% to 32% on a small list may be noise. Among 200 emails, that is 16 fewer people; a holiday can explain it. From 40% to 18% is not noise.
Five causes cover almost every case:
| Cause | Typical sign | How to confirm |
|---|---|---|
| Lower delivery, spam | Sharp sudden drop across groups | Test Gmail, Outlook and Yahoo; SPF, DKIM, DMARC headers |
| Changed list | New or old contacts added before sending | Compare opens among previous recipients only |
| Worse subject | Moderate drop, normal delivery | Resend to nonopeners with another subject and compare |
| Time or date | Holiday eve or Carnival Saturday | Check calendar; compare business-day sends |
| Changed measurement | Tool updated or service switched | Read update notice; compare clicks instead of opens |
How to investigate step by step
- Delivery. Send the same email to three of your accounts at different providers. If any lands in spam, stop: delivery is the issue. See https://avilaops.com/guias/email-caindo-no-spam-sem-saber/.
- List. Check for new contacts. Old spreadsheet imports dilute rates and generate bounces hurting the following send.
- Subject. Compare the last two subjects side by side. Dollar signs, capitals, “free” or vague promises may trigger filtering or ignoring. Criteria: https://avilaops.com/guias/assunto-de-email-que-faz-abrir/.
- Timing. Record both dates and times. Tuesday 10 a.m. versus Saturday 8 p.m.? Check holidays too: Carnival Monday or Tuesday naturally performs worse.
- Tool. Check changes to open counting. Apple Mail already inflated numbers; tools now discounting that show declines without changes on your side.
If none explains it, inspect clicks and replies. If those did not decline, the open-rate drop is measurement and you can move on.
When is resending to nonopeners worthwhile?
Only after confirming good delivery. Resending with compromised delivery sends the same email to spam twice with twice the reputation damage.
With delivery confirmed, resend once with a different subject three to five days later. People not opening either attempt leave the next send and enter a lower-frequency reengagement list.
What to do now
Test delivery first. If the sending address is still free or lacks SPF, DKIM and DMARC, declines will repeat. Email on your domain, authenticated from the start, for R$ 10 per mailbox/month, ready today: avilaops.com/email-profissional or contact us on WhatsApp: wa.me/5517997811471.
Frequently asked questions
Opens fell after changing sending tools. Is that normal?
Common. The new tool uses different servers not yet in your SPF and measures opens differently. Check SPF and compare clicks across tools before concluding.
Does Carnival reduce open rates?
During Carnival, yes; they normalize the following week. For sends from Carnival Saturday through Ash Wednesday, compare with the send before that period rather than a holiday-free month.
Should I delete contacts who never open?
Separate rather than delete. Those inactive for six months enter a rare-send group, monthly, asking directly whether they still want messages. Remove nonresponders. This protects everyone else’s delivery.
Turn what you learned into your next step.
Tell us about your company and what you want to improve. We can explore the right tools, integrations or custom project together.