email metrics

Often times, when reviewing email campaign results, it’s easy for marketers to get side-tracked or develop tunnel vision when reviewing very basic outbound email metrics. Can an email stats report be boring? Certainly.

However, in order to truly appreciate the depth of your data, you must know what the most important goals are in every campaign and hold them close to your chest. These are usually items like opens, calls to action or conversions, and website traffic. In pursuit of those goals, it’s always nice to understand what your basic email reporting metrics are telling you, and how their output relates to your campaign distributions.

Now there are obviously a whole lot of variables that play into a successful email campaign. To simplify this, I like to tell people that a successful campaign is really just a good marriage between strategy and relevant data. If that marriage becomes splintered, then the very first place you’ll notice this will be in the outbound email metrics report. That is where the rubber meets the road, folks. Analyzing email metric reports is an excellent way to help review and sometimes diagnose issues with your targeting, data, or even deliverability. It can also be an excellent window into the quality of a campaign’s performance and how it is reacting with your intended strategy.

Before we go any further, I must issue a warning. Much of this information is likely going to be meaningless if you’ve divorced your campaigns from email sending best practices. If you have not embraced the most rudimentary best practices (DKIM, SPF, Postmaster Tools, etc.), then you really are undermining the true potential of your email blasts. Your main risk: unintended consequences that result from bad decisions, which in turn are bad precisely because they were springboarded off of incorrect or imprecise data about deliveries and other metrics.

Below are the basic, core deliverability metrics that can oftentimes tell you how best to make guided changes in your email strategy.

1. Delivery rate = Deliveries / Sent

This metric will help tell you the mailable status of a list, each time you send.

Everyone wants 100%, and with best practices, consistent sending cadence, and good list hygiene it’s possible to get very close. Generally speaking, a delivery rate to all senders should be above 90%. I just talked with a client of mine who sent a million emails and received a 99.5% Delivery rate with a near 20% Open rate – Wowza! Ahh…the fruit of best practices.

If you’re encountering a low delivery rate, then (depending on what’s showing up in the bounce logs) you may be incurring an element of blocking. Cross-reference your sending IP and domain with known blacklisting agents to make sure there aren’t any issues. You may be getting throttled somewhere. Also note, if a high delivery rate is coupled with an unusually low open rate that it could be a red flag pointing to increased spam folder placements.

2. Open rate = Unique Opens / Deliveries

This will be the metric that influences your spending strategy the most.

The anticipated metric here is going to vary depending on a multitude of variables that frequently change. After all, not every campaign is created equal. Similarly, neither is data, nor its relevance to the subject matter.

It’s always a good practice to utilize an A/B testing approach in order to determine which Subject line and From name will generate the most response before you distribute an email to the balance of a campaign’s targeted universe. This is what sampling is all about, everyone. Metrics for 10% of your list will generally be indicative of what you can expect from the entire list as a whole, similar to how pollsters in an election can project a winner with only 10% of the votes being counted.

Once the email send is done, identify users who have engaged and make a segment for them. Furthermore, consider segmenting your entire target list by degree of engagement, and send to the most engaged first on your subsequent email campaigns. Engaged individuals have not opted out or complained yet, so you want to make sure they receive emails first, every time.

3. Hard bounce rate = Hard bounces / Sent

This metric describes emails that have bounced back as undelivered without having been accepted by the recipient’s mail server.

Common reasons for hard bouncing emails are using old/stale data, having fake email addresses on your lists, and sending email to addresses on unconfirmed or single opt-in lists. An acceptable rate for hard bounces is anything under 1% of the total send. Elevated hard bounce metrics will create a much greater risk of blocking, too – particularly if you’re warming an IP address or have no sending history. I would recommend a list validation to cut down the number of bad emails in your list prior to sending, which will in turn lower the hard bounce rate.

4. Soft bounce rate = Soft bounces / Sent

This metric is used to describe an email that has bounced back to the sender as undelivered after it has already been accepted by the recipient’s mail server.

Common reasons for soft bouncing are spam filters, rate-limiting, over quota (graylisted), iffy content, or policy issues set by the end users. An acceptable metric for soft bounces would be anything under 5% of the total send for engaged users and under 10% for non-engaged users. Anything greater than that, and additional wide spread rate-limiting or blocking may start to occur. Unusually high soft bounce metrics can often times lead to the discovery of a damaged sender reputation and possibly a stiff dose of blacklisting.

5. Spam complaint rate = Spam complaints / Deliveries

Spam complaints are different from unsubscribes. When people unsubscribe, that action is handled internally by the ESP, and there is no effect on your sender reputation.

When someone reports an email as spam or junk, it is documented by the receiving ISP. It’s then counted into a spam complaint ratio, which the ISP uses to help determine whether future email sends should be blocked. Every ISP’s threshold for spam complaints is different. An acceptable rate is typically under 0.1% of your successful deliveries.

High spam complaint ratios can also be symbolic of continued delivery to previously opted-out recipients, elusive unsubscribe links, confusing opt-out policies, or because the recipient never wanted to be on the list in the first place. It is for these reasons that I like to make the unsubscribe link as prominent and as visible as possible in the content. If someone doesn’t want to be on your distribution list, then it’s best to give them an easy, obvious way to opt-out. Don’t give them another reason to hit the spam complaint button.

If you’re prospecting, it’s a great practice is to send an opt-out campaign. I’ve done this before on many occasions if I know that we are sending to unengaged, purchased data. This is simply a message that states who you are, what you’re selling, and gives the user an opportunity to view your message along with a few opportunities to unsubscribe in the content. Not all marketers may agree with this strategy, but if you want to deter spam complaints and remove uninterested users at the same time this is a good way to go about it.

One last note on email metrics:

Got new/untested data? Remember to cleanse and verify all data as often as possible, and prior to delivering for the first time. If you’re unable to do that, then sample out a small fraction of the list and then review the above basic email metrics prior to sending out the balance of your new/untested assets.

Best Practices in Email Deliverability

The art of successful email marketing depends first and last upon proactive deliverability management. Check out Act-On’s eBook, “Best Practices in Email Deliverability” and learn tips and tricks you’ll need to help you manage the critical factors that affect the deliverability of your email messages.