Email marketing ROI: How to measure it correctly.


Email marketing ROI is vital for email marketing to be rewarding. However, tracking the wrong metrics can lead you to the wrong conclusions and have a negative impact on the deliverability of your newsletters - and your business.

In this section we will cover:

  • Important data to keep track of
  • Metrics that directly affect deliverability versus those that don't really matter to see if your content resonates with subscribers
  • A basic framework for your monthly reports

Key metrics for email marketing ROI

Most businesses are constantly monitoring key email metrics to understand what's working and what's not. But how can you be sure you're looking at the right metrics, especially as industry changes like Apple's mail privacy protections make key performance metrics less reliable?

In this section, we'll cover how senders can track email marketing campaigns to get a more accurate picture of the ROI (Return On Investment). So let's go!

The way you measure your email performance can reveal small issues before they cause bigger problems in the amount of revenue. Let's talk about some of the data you'll need to look at to get an accurate picture of your campaigns. I like to divide them into metrics that directly affect your email delivery and those that don't.

Rate of delivery to the incoming mail envelope (IPR)

As I mentioned earlier, it's the best way to measure your email delivery. Inbox Placement Rate is the percentage of emails delivered to the inbox rather than the spam folder.

There are several ways to improve IPR

  • Get consent. Your subscribers should indicate that they wish to receive your newsletter and not be automatically opted in, and you should set expectations about the frequency, the value you provide and give them a sense of security that you will not send them unsolicited content. Never use email collection software or even buy a mailing list. Emailing subscribers who have no interest in your product/service is the worst thing you can do.
  • Be legal. There are many laws governing the sending of email, such as the law GDPR. Make sure you comply so that your internet service providers (ISPs) do not take action against you.
  • Integrate email marketing into your overall marketing plan. Always make sure to integrate your email marketing program to be part of your larger marketing plan, where you set goals and define your KPIs. Don't forget that marketing is Omnichannel and all channels have their importance.
  • A/B Testing. The critical element of a successful email marketing campaign is to experiment-test and monitor to find out what works and what makes your email list more or less appealing.
  • Use DATA. With the help of your data, you can design a plan to segment and personalize your emails to match them with the audience you want.

Click-to-view ratio (CTR)

This refers to the ratio of unique clicks to the number of times a link or links within an email appear in the message to the total number of recipients. It is usually expressed as a percentage. A high click-to-view ratio sends a positive message to MBP (Mailbox Provider) that recipients want to receive your emails, making them more likely to be delivered to your inbox. Now that open rates are less reliable due to Apple's mail privacy protections, which I'll discuss in a minute, many businesses now prefer clicks as their preferred method of tracking audience engagement.

Bounce rate (bounce rate)

This is the percentage of emails that bounce (not delivered) out of the total volume of emails sent in a campaign. These can be divided into hard bounces and soft bounces.

The soft bounces (Soft Bounces) are caused by a temporary delivery failure. Delivery is often attempted several times in a single period of time. These can happen when the recipient's mailbox is full, the mail server is down, or your email message is too long.

The hard bounces (Hard Bounces) is the result of a permanent delivery failure. There will be no repeated attempts to send these messages. These may occur when the recipient's address no longer exists or the recipient's address is unknown. Continued sending to these hard bounce addresses is a red flag for email providers and usually indicates non-maintenance of a list or incorrect subscriber acquisition practices (e.g., paid lists). Many ESPs have built-in suppression trigger rules associated with hard bounces and it is vital to check and make sure they are configured for your program. It is rare to see a zero dropout rate. But if you see dropout rates suddenly increase from your usual rate, it's time to consider damage control. In general, an abandonment rate above 2% is worth watching out for.

Complaint rate for SPAM (SPAM COMPLAINTS)

This is the percentage of emails sent to the spam folder by your subscribers out of the total volume of emails sent in a campaign.

Microsoft reputation sender data (SRD)

This is a program created by Microsoft that any email recipient can subscribe to. Microsoft sends specific emails to these subscribers so they can vote and let Microsoft know if they believe the email is unsolicited. Because of the way they are collected, these votes have a big impact on your deliverable.


This metric is the percentage of opened emails out of the total number of emails sent. However, this metric should be taken with a caveat. Apple introduced Mail Privacy Protection (MPP) with iOS 15 in 2021. This new feature hides tracking pixels from collecting information, denying senders the ability to know when recipients open an email. How does this happen? When a user selects MPP, Apple will preload email images before delivering them to the user. This way, the tracking pixel will be triggered even when the recipient doesn't actually open the email. Keep in mind that open rates to Apple Mail users are now higher than actual.

Rising metrics for email marketing

Now let's take a look at the metrics that do not directly affect delivery. These are still important to monitor to determine if your content is resonating with subscribers.


This is the percentage of subscribers who clicked the unsubscribe button out of the total volume of emails sent in a campaign. In terms of deliverability, it's always better to receive an unsubscribe than a spam complaint. This is why we recommend always keeping the unsubscribe link visible in your email.


This is the growth rate of new subscribers to your email list for a specified period.


This is the percentage of emails forwarded or shared out of the total volume of emails sent in a campaign.


This is the percentage of subscribers who follow the call to action in an email marketing campaign. For example a "Buy Now" CTA in which a subscriber clicks and eventually buys a product.


This metric allows you to know how much revenue you collect on average per email you send.

I know, that's a lot of definitions. However, understanding the metrics in this section is key to improving your campaign reporting.

If you want to refresh the measurement analysis, start with this basic framework:

  • Find out what data you have available and make sure you understand the metrics we have just defined.
  • Define key performance indicators (KPIs) and decide which email metrics are most important for the company's email marketing. This will vary depending on the size of your organization and the number of emails you send.
  • Define and set targets in each key performance area. The use of SMART targets helps. Perhaps what you are primarily interested in is reducing email abandonment rates or growing your subscriber list. Whatever your goals are, make sure they are specific, measurable, achievable, relevant and measurable over time.
  • Track progress manually or with the help of an email marketing platform, such as Klaviyo.

When it comes to campaign reporting and Email Marketingng ROI in general, the old adage applies: If you can't measure it, you can't improve it. Make sure you track the metrics that matter to give your email program the best chance of success.

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