Before measuring deliverability, it might be a good idea to understand what you want from your measurements. Above all else, you want to avoid an incident.
You can separate deliverability incidents into four categories:
Incorrect email classification: Most inbox providers classify certain emails as important or priority while others are filed into one or several other mailboxes (e.g., the promotion folder in Gmail). Sometimes your emails might go to the wrong mailbox. This error could happen with an order confirmation, which might be misdirected as a promotion when it should go to the priority mailbox.
Marked as spam: This is, without a doubt, the most common incident. Instead of being delivered to the inbox, your emails are marked as spam by the email client.
Blocked: Having your emails rejected and not accepted by the destination server is even worse than being marked as spam. In this case, you should usually - but not always - receive a block bounce type error.
Blacklist: If your IP address or domain name ends up on a blacklist, you might find your emails blocked completely across all inbox providers. We’ll go back to blacklists in chapter 5 and tell you which ones are most important.
Understand the Destination
Before introducing you to deliverability KPIs, it’s important to understand the idea of destination.
This notion groups email addresses together according to the inbox provider. Imagine a list of email addresses (all entirely made up for this exercise):
All ten email addresses above have different domains. However, some of them belong to the same companies and use the same spam filters and reputation scores:
Microsoft: live.com, outlook.com, msn.com, hotmail.com
Orange: orange.fr, wanadoo.fr
Yahoo!: yahoo.com, ymail.com
SFR : neuf.fr, sfr.fr
You’ll see why this is relevant in just a moment!
Analyze Delivery Performance
Check the Bounce Rate
Bounces, along with opens, are one of the most precious deliverability indicators.
They can indicate a block due to:
Poor reputation.
Excessively high email volume.
Poor-quality database (targeting inactive addresses or poorly qualified/non-opt-in addresses).
Bounce rate = number of bounces/number of emails sent.
If you’re aware of your bounce rates by destination, you may be able to work out when and from which destinations you are blocked.
Check the Open Rate by Destination
Though other indicators can alert you to an incident (the bounce rate, for example), the open rate is the most important and the most reliable.
If your open rate for Microsoft inboxes (Hotmail, Live, Msn, Outlook) halves overnight while other destinations remain stable, you’ve got a delivery problem with Microsoft.
Check the Dissatisfaction Rate
Go back and review the part about dissatisfaction rate if you need a refresher. Here’s the formula again:
Dissatisfaction rate = unsubscribe clicks/total number of clicks.
The dissatisfaction rate can be mainly used to identify the types of campaigns that can harm your sender reputation.
Let’s Recap!
Deliverability incidents can be organized into four categories:
Incorrect classification
Marked as spam
Blocked
Blacklisted
In deliverability, a destination is a group of several domains that use the same anti-spam infrastructure.
Bounce rate by destination lets you spot when and where emails are being blocked.
Open rate by destination lets you identify emails marked as spam or being blocked from entering.
In the next chapter, we’ll look at ways in which you can avoid deliverability incidents.
