Troubleshooting sharp increases in complaint rates

You see a sharp increase in complaints at one or more mailbox providers.

Common causes
Many scenarios can cause a sharp increase in complaints: 

  • You stopped using opt-in permission methods with subscribers
  • You recently used a high-risk list acquisition method such as list purchase, list harvesting or co-registration
  • You do not have or changed your list hygiene strategy
  • You accidentally sent email to a suppression list
  • You sent a new email stream to subscribers without their consent
  • You suddenly increased the sending frequency of email to your subscribers during a major holiday
  • You updated your branding (which changed the look and feel of your content) without notifying subscribers
  • There was a breakdown in the complaint-handling process
  • An ad-hoc email was sent to the entire list file
  • Your sending volume dropped significantly in a short period of time relative to your average sending volume (aka complaint hangover)

Products and data used to troubleshoot

  • Return Path Platform can show which campaigns are receiving complaints over the last 7, 15, and 30 days. You can also use it to look for trends over time. For example, you may see complaint spikes on certain days or within certain time periods.
  • Inbox Insight can be used to check your campaign's read rate as well as complaint rate, which can be useful in determining how engaged your subscribers are with your email.
  • Email Client Monitor can be used to see which subscribers are opening your emails and on what platforms so you can optimize your mailing program for them. You can include custom tagging and a subscriber ID to receive detailed information about your subscribers and use this data to help determine what segment, or segments, are complaining about your email.
  • If you are Certified, you can see 30 day's worth of aggregate data in the user interface, or download 30-day daily data to see when complaints occurred at Yahoo!, Microsoft, and Cloudmark to help you determine what may be driving complaints.
  • Email Service Providers (ESPs) may provide feedback loop complaint data through their sending platform or from a report for each mailbox provider. Contact your ESP account representative for more information about how you can access complaint data.
  • Internal feedback loop complaint data is obtained from your company's mail system. Contact your email administrator or IT department to help you pull complaint data for each mailbox provider.

To isolate the cause of the problem:

1. Determine if the complaints suggest that a recent change to your mailing program caused dissatisfaction.

Review the list of possible causes above to see if any of those scenarios could be a possible reason for the complaints. An unexpected increase in sending frequency, new list acquisition sources, and sending to a suppression file are the most common reasons for sharp increases in complaint rates, so check those first.

2. Determine if the complaints are coming from a specific segment of your list. 

For example, are they coming from:

  • Less engaged subscribers?
  • A new group of subscribers recently added to your list?
  • Subscribers from a specific acquisition source?

Examine the segment to determine what sets it apart from the others. For example, if you recently added a new group of subscribers to your list and that group has a higher complaint rate than the rest of the list, examine how that list was acquired and whether the mailing you sent met the expectations that were presented at the point of collection. 

3. Review whether your sending volume is consistent.

You may be experiencing complaint hangover. For example, senders typically send a significantly higher volume of mail in December to encourage customers to purchase gifts, then taper off after December 25th. It is common to see a spike in complaints the first business day in January when subscribers  check their work email and complain about the emails they received. Complaint rates are calculated by dividing the number of complaints received by the number of emails delivered within a given time frame. The date the campaign was sent is not factored into the rate.   

To avoid complaint hangover, maintain a consistent sending volume. If this does not fit your business needs, be aware of the possibility of complaint hangover. If the spike is a result of a decrease in volume, then watch your complaint rates for several days to see if the complaints normalize. If they do not, look to other potential causes for the spike. 

4. Determine if the complaints are associated with a specific IP address, brand, sending domain or email stream.

Organizations with a more sophisticated email program can sometimes associate a sharp increase in complaints to a specific brand, IP address, sending domain or email stream. There may be multiple people in charge of different parts of the email sending process, so work with them to ensure email best practices are being followed. 

Complaints occur when the email sent to subscribers does not meet their expectations. A preference center is a good way to help reduce complaints since it allows subscribers to choose the content and frequency of email they want to receive.



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