Comment Spotlight: The Most Important Email Stat?

From time to time comments on the blog are worth discussing with everyone in a new post. Friday’s post on confirmation rates sparked a discussion of other other stats that we can measure and improve. Glenn voiced a question that I think all of us have asked at some point: “In looking at each email list you have available, what sort of metrics are the best to monitor? I think if you had to pick one metric, overall conversion rate is probably best[.]” So Is There A Single Best Metric?

From time to time comments on the blog are worth discussing with everyone in a new post.

Friday’s post on confirmation rates sparked a discussion of other other stats that we can measure and improve.

Glenn voiced a question that I think all of us have asked at some point:

“In looking at each email list you have available, what sort of metrics are the best to monitor? I think if you had to pick one metric, overall conversion rate is probably best[.]”

For a lot of people, email stats are a way to monitor the “health” of their campaigns. We want to see, at a glance, how profitable our email marketing is.

But before we can begin to answer his question, we should address the two bigger questions here:

Is there one “best” or “most important” email metric?

If not, are some helpful metrics that we can look at, and what do they tell us?

Is There One Superior Metric?

Glenn’s comment reminded me of the question, “If you were stranded on a deserted island and could only have one CD with you, what would it be?” It’s a fun exercise, but is/should be entirely theoretical.

Here’s the thing: if you restrict yourself to looking at one stat, you miss out on information that other stats tell you, and the potential gains that your reaction to those other stats could bring.

Take conversion rates, for example. They give us a broad view of our success. If you know your conversion rate, how many subscribers you’re communicating with, and what your profit is per conversion, you can easily calculate how lucrative your email campaigns are.

Ignore a metric, and you ignore the potentially useful information it contains.

But what if you want to improve your conversion rate? What’s the first step you take?

A lot of things factor into how effectively your email campaigns convert prospects to customers. Like subject lines, and “from” addresses, and your calls-to-action. If all we look at is our conversion rate, we’re less likely to see that (for example) maybe our subjects are poor, or maybe our calls-to-action work better as images than as text.

So What Are Some Basic Stats To Keep An Eye On?

This is by no means an exhaustive list of possible metrics, but if you’re not sure what to track, this is a good place to start.

Open Rate

What it tells you:

For HTML messages, tells you what percentage of people opened your email. Often used to judge the effectiveness of subject lines, days/times to send messages and “from” names/addresses.

Caution: Take with a grain of salt.

Opens are tracked using a 1×1 image, and are skewed by preview panes (people don’t read your email but their email program loads the image) and image blocking (people read your email but the tracking image never loads).

The usefulness of opens is comparing and tracking their change over time to see if more or fewer subscribers appear to be opening your messages.


What it tells you:

Shows what percentage of subscribers clicked links in your messages. Often used to judge the effectiveness of a link’s presentation (location, color, size, image vs. text) as well as message body copy.

Caution: Click-through rates can be misleading, too, if you look at them by themselves โ€” if fewer people open your email, fewer chances are fewer people are going to click your links. A message that had fewer clicks may still have had an effective body, but just a really low open rate.

You may find the next stat more useful for measuring link/body effectiveness.


What it tells you:

Click-Through Rate divided by Open Rate. For example, a message with a 40% open rate and a 20% click-through rate has a clicks-to-opens rate of 50%.

Attempts to give you a more accurate picture of how effectively you drive people to click your links by isolating the part of your list that actually opened your message.

There are tons of other stats that you could come up with as you go, but when looking at the effectiveness of your emails, these three are a good place to begin.

And yes, you’ll want to keep track of your conversions too ๐Ÿ™‚

Want to know more about this or any other email marketing topic?

Email us your suggestions!



  1. Andrew Foss

    10/26/2007 8:17 am

    One Best Stat? No – It completely depends on the campaign. I promote in 6 different markets, each with different customer types. Some, I am looking to develop through multi-stage campaigns. Consumers, I am looking to convert as quickly and as oftyen as possible.

    I also use email to test: my landing pages, specifics about my email, etc. I use all the stats I can get in order to improve my understanding of what is going on – with the final desired result of increased sales conversion.

    It just depends on what you hope to accomplish

  2. PurpleRain

    10/27/2007 1:15 pm

    I would like to see the Verifying Opt-In and Open Rate report/statistics in such manner:
    How much % verified/open in 24 hours after subscription/broadcast
    …in 48 hours
    …in 72 hours
    …in a week

    So that we can know that (Especially Open Rate) there are actually how many people we can strongly influence within our control.

    Those who open message within 24 hours tend to be closer to us. For example I have a list that its open rate is around 50%, half of it open within 24 hour since I made the broadcast. I observe it by myself, if there is a report function for this it will be nice.

    It means that, 25% of my subscribers will open within 24 hour after the message was broadcasted. But to climb up to 50%, it takes whole week to achieve that.

    So it gave me a signal:
    1. I have 500 subscribers (and growing around 20 people a day), but I can only influence half of them, because another half of them never open my email!
    2. Among these 250, 125 of them will open my message "on the spot" once they check their mail, because they open the mail within 24 hour.
    3. Another 125 of them, they just take their time. It will take a total of 7 days for them all to open up the message.

    If Aweber can provide report as stated above, then I know I should focus on those first 25% who open my email within 24 hour, they are my fans and supporters. If I have any price and offer, I should bear them in mind when I make decision.

    For example, take my case:
    25% open within 24 hour

    Let’s say, assumed that another 15% will open within subsequent 48 hours, it means that:
    40% of my list will open within 3 days after message has been broadcasted. another 10% will take remaining 4 days.
    It also means that, from the total number who opens my message, 80% open within first 3 days.

    So now if I wana make a product launch and made an offer, I should only target the 80% population.
    My offer should have a maximum of 3 days, because it is the time frame most of my list open the message.

    Am I clear enough on making my point? If not please ask.

  3. Gidon Ariel

    10/27/2007 5:44 pm

    This Basic Stats table is an excellent presentation for a relative newbie. I suggest fleshing it out a little and giving it its own page.

  4. Sira Sudhikam

    10/27/2007 9:20 pm

    Dear Justin,

    Yes, I tend to agree with your comment that the changes of the parameters tend to give us insight on how we are doing with our campaign.

    Just of my curiosity,

    1. Why would you should the "Read More" button which is a graphic than a ususal HTML link in your broadcast message? Some (I guess almost all now) email programs have a "picture" blocker. So how could you reach your readers who do not allow your button to be appear.

    2. How could I create a highlight box (the light blue box) as you have done on your latest broadcast.

    Thank you in advance

  5. Stacey Barr

    10/29/2007 2:44 am

    I agree – there can never be one ultimate measure of campaign performance. And I really advocate that before anyone decides which measures they really need, they’ll find it valuable to first write down the questions they have about their campaign performance.

    As Andrew says in his comment above, he’s got different purposes for different campaigns, and that means he’ll have different questions he wants answered about how each campaign works.

    And so the questions depend on purpose. Do we all think clearly about the purpose of each campaign before we design and run it?

  6. Justin Premick

    10/29/2007 8:17 am


    Thanks, that’s a good idea and something we should add to the other tracking information in the Knowledge Base.


    1. We’ve been split-testing text vs. image calls-to-action in our broadcasts to see which gets more clicks. Looks like you got a version with the image. Did you click it? ๐Ÿ˜‰

    2. For the boxes on our blog and elsewhere on our site, we use DIV tags and apply some CSS. You can read more about DIV tags here.


    You can see a breakdown of your confirmations by time using this report (requires login).

    We don’t currently offer that for open rates, but I’ll let our developers know you’re interested in seeing that ๐Ÿ™‚

  7. Carlo Selorio

    10/29/2007 9:54 am

    I’ve always keep track of conversions. Of my cickthroughs.

    I think its the most important part of email marketing.

    In the end that’s why we use it in the first place…

  8. Email Testing For Quality Assurance and More

    12/9/2009 4:47 pm

    […] Limitation: Any type of measurement requires interpretation to get actionable insight. […]