9 things that matter when Reaching the inbox

Email deliverability is a moving target due to a constantly changing industry. Something that worked last week may not work this week. This year, in particular, 2018 has been difficult to predict deliverability changes, with the implementation of the EU’s GDPR which governs rights to privacy for Europe, having affected filters and deliverability worldwide.

1. CAN-SPAM Matters
Each separate email in violation of the CAN-SPAM Act is enforced by the FTC and subject to penalties of up to $41,484, so non-compliance can be costly. But following the law isn’t complicated.1

Compliance Basics

  • Don’t use false or misleading email headers ever
  • Avoid deceptive subject lines
  • Identify your message as an advertisement
  • Provide a valid physical address
  • Make it easy for recipients to opt-out of future messages
  • Honor opt-out requests promptly
  • Carefully monitor your employees, affiliates, and sub-contractors
  • All emails must contain valid opt out mechanism, and be honored within 10 days


Bounce rate, complaint rate, sender reputation and ultimately your return on investment are heavily influenced by keeping a clean data set. Cleaning your list can improve your inbox placement by reducing your bounce rates, toxic data hits and complaints.

Bounce rates
A validation service will help catch and correct spelling and syntax errors (like making sure .com doesn’t stop at .co or having two @@ symbols) and remove plain old invalid email addresses.

Toxic data
An email validation service monitors trends of millions of contacts and can predict the likelihood an email address is a spam trap. There’s a few ways spam trap addresses can make it onto your marketing database, but failing to remove them means you could be blacklisted or blocked.

Complaint rate
Email validation can weed out addresses for folks who don’t want your emails and regularly complain and report commercial email as spam.

Bounces, complaints and anti-spam measures all play a role in determining your sender reputation. Your reputation strongly affects inbox placement, which can be the difference between your marketing email landing at the top of your customer’s inbox and being dumped in their spam folder.

Spam filters do look at content and landing pages, so keep that in mind when crafting your message.

Even though a word may be relevant to physicians, if it is a typical “spam” word, the filters will block your message.

  • Make sure security certificates are not expired.
  • Emails under 100KB have the greatest likelihood of passing through spam filters and avoiding being clipped in Gmail.
  • 600px max-width.
  • This width should give you plenty of space for content and will fit nicely on most web and desktop clients.
  • Optimize for mobile-more than 60% of our email views are on mobile devices.

    • Often optimizing can be as simple as using a single-column design.
    • Easier to code and keep looking good across clients.
    • Easier for readers to scan a single column of material.

  • Account for different email clients- Focus on consistent branding and being easy to read and click on all email clients. It’s very difficult and often not useful to try achieving “pixel perfection” and exact replication on every single email client.
  • Always test using Litmus or Email on Acid for renderings in relevant clients.
  • Add width attribute for Outlook (not just inline style).
  • Use alt tags on all images.
  • Write quality code. Poorly written HTML means the spam filter can’t read it. If the spam filter can’t read it, it may send you to spam just to be safe.
  • Include physical address and unsubscribe links, and follow all CAN-SPAM laws.


  • Run through subject line tester, such as: Send Check It3 and don’t re-use subject lines for subsequent deployments to the same list.
  • Entice curiosity, you want to make them curious enough to open, but without being so cryptic that the subscriber hasn’t a clue as to what you’re talking about.
  • Insert numbers. Numbers in your subject line are visually magnetic.
  • Speak in the language and style that your subscribers use themselves, especially when talking with their friends or colleagues.
  • Utilizing preview text in conjunction with the subject line can help increase open rates.4
  • Preview text is supported by most major email applications, the character count they show does vary, so it’s often a good idea to:

    • Keep preview text on the shorter side.
    • Include main points and buzzwords towards the front.
    • Include a sense of urgency call out.


  • Optimize your email for mobile devices, since 60%+ of physicians are opening on mobile.
  • Prioritize content hierarchy and scanability.
  • NEVER use image only email.
  • Images should make up less than 1/3 of the total creative.
  • Do NOT use web font, use universally-supported fonts via inline CSS:

    • Sans-serif: Arial, Arial Black, Tahoma, Trebuchet MS and Verdana.
    • Serif: Courier, Courier New, Georgia, Times, Times New Roman.
    • Monospace: Courier, Courier New.


  • Make sure security certificates are not expired.
  • Don’t use URL shorteners like bit.ly and ow.ly. They are often abused for spam because they can hide the true nature of the sender.5

What recipients do with your email plays a large role in both delivery and inbox placement.

  • Send relevant information to help increase engagement with your brand.
  • Segment your list appropriately to tailor messaging.
  • Email more often to people engaged with your emails, and less often to those who aren’t.

Filters, email clients, and your audience are always evolving, so always be testing. A/B testing is easy and can help you get to know your audience better and more effectively communicate.

  • Test everything about your email. Content, colors, subject lines, send date/time, etc. to help improve results.
  • Review your campaign reports over time to see if there are any patterns to focus on improving.
  • Example: Instead of resending to non-openers, retarget your openers who didn’t click through or even all openers with a slightly adjusted message.

Know your goals and KPIs going into a campaign and review metrics both in the short term, between campaigns, and over time.


1. https://www.ftc.gov/tips-advice/business-center/guidance/can-spam-act-compliance-guide-business
2. https://www.towerdata.com/blog/bid/113800/6-challenges-email-validation-helps-you-overcome
3. https://sendcheckit.com/email-subject-line-tester
4. https://sendgrid.com/blog/perfecting-your-email-preview-text
5. https://blog.aweber.com/email-deliverability/link-shorteners.htm