Email Marketing: 7 Key Metrics to Monitor and How to Improve Them

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“What's not measurable isn't improvable”.

So goes the old saying that managers from all over the world love to repeat from time to time, especially when they turn to colleagues who deal with marketing.

There are some measurable actions for marketers, such as email marketing campaigns.

Key metrics may be misleading, so it is good to know what to focus on.

Despite the defined metrics should always be linked to the objectives to be achieved, there are some that can not be overlooked.

1. Spam Score

It’s wise to avoid getting your emails flagged as spam at all cost. Before sending any email, ISPs provide a spam-score that indicates the likelihood of being filtered out and not being read by the recipients.

There are several tactics to avoid ending up in the spam filter, for example reducing the number of links in the email and coming up with great subject lines which boost response rates and engagement.

How to Improve It

Of course, you need your spam score to be as low as could be allowed.

A high spam score will make it hard to get your messages conveyed to the inbox of your beneficiaries.

Spam scores are explained by a numerical worth from 0-10. The lower the better.

Here are few points you need to pay attention, as they will increase your spam score:

  • Subject begins with dollar sign, discusses losing pounds, includes G.a.p.p.y-T.e.x.t or is all capitals
  • Text includes “Dear (…)”, the word “FREE”, home refinancing or lowest price
  • HTML font dimension is big or has a little ratio of text to image area

The rundown of components that these spam filters utilize is huge, included strange and funny elements, like information on how to get “larger body parts”.

To enhance your spam score (remember, you want it as low as possible), investigate the current rundown of errands performed by SpamAssasin – and remove the highest possible number from your email marketing campaigns.

You can run some tests with your email, before sending it out to your subscribers.

One simple path is sending your message with TEST before your Subject Line (i.e. “TEST My Mailing List”) to

They will return with a spam score and a list of the particular components of your message that help increase that score.

It's important to understand your spam score and take actions to improve it.

2. Open Rate

The open rate is one of the basic metrics, and simply shows how many emails have been opened.

How to Improve it

Analyzing this data over time can give indications about the preferences of your target and lets you understand, for example, which days are more easily open your email.

You can improve this metric by A/B testing your emails. Optimizing your email marketing campaigns can be the difference between a breakeven campaign or a profitable one, and many marketers often overlook or fail to analyze their campaigns through split testing.

But keep in mind the several elements which may increase your spam score!

photo credit: melenita2012
photo credit: melenita2012

3. Click-through Rate

The click-through rate is one of the most important metrics, because it shows how many people have interacted with the mail sent and therefore have clicked on the included link.

This is an important finding, because although these people may not have been converted into customers, they have found, however, sufficient evidence of interest in the mail.

How to Improve It

While testing your email marketing campaigns, you will get a feeling of your audience needs and what they like to read in your messages (remember that certain content works better on specific channels, not necessarily the emails).

Measure the effectiveness of your campaigns, by checking which emails performed the best.

Then ask yourself:

Did you push a specific argument?

Did you utilize a different tone?

How structured were your calls to action?

Taking into account what you find, make comparative messages that typify a portion of the strategies, which made your previously messages fruitful.

Remember : Run A/B test with your messages to help you enhance the click-through rate. Take a look of the CTR of each email, as it will help you figure out what email components are best.

4. Conversion Rate

This is a key metric to understand if your email marketing campaign has had the desired effect.

The conversion rate is the percentage of recipients who have interacted with your email by clicking on the link back to the website and have subsequently completed a desired action.

This action can be, for example, filling out a request form, or even purchasing a product offered or advertised in the email.

How to Improve It

Pay attention at your landing page dashboard.

Can you find the pages which convert more?

You should also check the ones with the most views.

Inspect your most successful landing pages, to repeat the high performance.

Was there a particular content?

Any specific optimization or personalization?

Study the single elements, in order to replicate the pages with best results.

5. Bounce Rate

The bounce rate is the percentage of rejected emails.

A stable bounce rate could indicate that in your mailing list there are wrong or undeliverable address, so be sure to check them.

A possible reason for a high bounce rate, instead, can be caused by problems with the email provider's server, so it may be useful to contact them.

How to Improve It

Utilize this metric to reveal potential issues with your mailing list.

You may face two types of bounce rate : “hard” and “soft”.

The soft bounce is when there is a temporary issue with a valid email address, like a full inbox or a problem with the receiver's server. You can get your email delivered when the issue is cleared or you may try to resend the message to subscribers with soft bounces.

Hard bounce is the consequence of an invalid or non-existent email address, so you won't be able to deliver messages to these users.

You want to remove all these subscribers from your mailing list, as you can get an increased spam score as result (ISPs consider bounce rates as one of the elements to label a sender as spammer).

Tip : all the users in your list should be acquired using a double opt-in. In other words, you need to have sent, which means that you should have sent those subscribers a message asking them to verify their email address (and their decision to be part of your mailing list).

In this way, you can avoid to collect wrong email address due to the bad typing in your opt-in and you are sure the user actually wants to receive your newsletter.

6. Complaint rate

It is also useful to monitor the number of complaints received to understand how your email marketing campaigns are perceived by subscribers.

There may be many reasons for a complaint, but the main ones are:

– the member has forgotten that he had given the authorization;
– mails have an inkling of spam;
– too many messages.

How to Improve It

Be sure to send a welcome email to new subscribed users.

A courtesy message to thank for being part of your mailing list and summarize the benefits of your content.

Tip : you can take the occasion of the welcome email to ask users to add your address to their emails book.

Dont' send too many messages and pay attention to activate again inactive subscribers, from time to time (you can do this by segmenting users who haven't open messages for a certain time and then targeting them with special emails, including promotions or freebies).

7. Unsubscribe Rate

People who decide to be removed from your list are also a useful indicator.

How to Improve It

For example, if you notice any peak of cancellation after a particular message, then you should check if your latest email were inappropriate, or if it has contained useless information.


Familiarize yourself with these key metrics will help you improve the results of your email marketing campaign.

From every element, you may take experience to improve your messages and create a newsletter as effective as possible.

Are you managing a mailing list?

What's your experience?

Please share your thoughts in the comments below, thanks!

Erik Emanuelli

Erik is a passionate traveler and serious blogger. He likes to write about online business on his main site NoPassiveIncome. You can check his new blog at Reviewz'n'Tips.

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6 thoughts on “Email Marketing: 7 Key Metrics to Monitor and How to Improve Them”

  1. Hi Erik,
    All the seven points you have stated are very true and helpful. As a newbie, I was completely unaware from these points. After reading the post now I am getting the idea about the Email marketing. Thanks for updating me.

    • Hello Gurvi,
      I’m glad you enjoyed the post, having you introduced email marketing.
      I hope these tips will help you, if someday you decide to start your own campaign.

      Thanks for your comment!

  2. Hi Erik,
    Nice to see you here. First of all i don’t have too much idea about Email marketing. All the 7 points help me to improve my email marketing and also its helpful to them who want to get a sure traffic from their email subscribers.

    • Hi Akash,
      I’m glad to know you learned something new from this post.
      Thanks for your feedback.

  3. These are really good article for all those who wants to start their email marketing. I do have a question for you, do you know any plugin using that I can grab name and email of all those who is going to download my themes and plugin but I do not want to send these email id to any email service like aweber or mad mini or mail chimp but this should be stored in my wordpress database.

    • Hi Rakesh,
      glad you liked the post.

      I’ve never heard of a plugin with those characteristics,
      may be you can try at forum?

      Thanks for visiting and commenting, Rakesh.
      Have a good week.

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