Definition
Out-of-office handling refers to the processes for managing automated reply messages that subscribers' email systems generate when they are away. These auto-replies — triggered by vacation settings, role changes or extended absences — arrive as replies to marketing campaigns and can distort metrics if not properly identified and filtered.
In large sends, out-of-office replies can number in the thousands. Counting them as subscriber engagement artificially inflates reply rates. More importantly, some out-of-office messages contain alternative contact information, forwarding instructions or role-change notifications that require human attention.
How to Identify OOO Replies
- Most auto-replies contain standardised headers including
Auto-Submitted: auto-repliedorPrecedence: bulk - Subject lines frequently contain predictable patterns such as "Out of Office" or "Automatic reply"
- Reply bodies often follow a recognisable template across an organisation
Best Practices
- Configure automated filtering to exclude out-of-office replies from engagement metrics
- Scan OOO replies for role-change or departure notifications that may indicate list decay
- Do not automatically unsubscribe subscribers who send OOO replies — they are temporarily unavailable, not uninterested
- Monitor OOO reply volume as a signal; an OOO spike during holiday periods is normal, but a sustained increase may indicate list quality issues
Related Glossary Terms
A/B Testing
A/B testing in email marketing is the practice of sending two variations of an email to a small sample of your list to determine which version performs better before sending the winner to the remaining subscribers.
ARPU (Average Revenue Per User)
ARPU (Average Revenue Per User) is a metric that measures the average revenue generated per email subscriber over a specific period, used to evaluate list value and campaign effectiveness.
Attention Rate
Attention rate is the percentage of email opens that last longer than 5 seconds, distinguishing genuine reads from passive opens, preview-pane views, or Apple MPP auto-loads.
Bounce Rate
Email bounce rate is the percentage of emails that were rejected by the receiving server before reaching the recipient. It is a key indicator of list health and data quality.
Campaign Internal Rate of Return (IRR)
Campaign IRR is the annualised return rate earned by an email campaign, accounting for the timing and magnitude of costs and revenue across the campaign's full lifecycle.
Campaign Lifted Revenue
Campaign lifted revenue is the additional revenue generated by an email campaign beyond what would have occurred without it, measured via a holdout group or statistical lift analysis.