What factors affect the deliverability rates of e-mail campaigns?

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Answer: With constantly changing ISP regulations and new filtering products entering the market every day, ensuring in-box delivery can be a daunting task. But it’s not rocket science. Here are a few factors that may be affecting your delivery rates, and some tips to improve your campaign results.

  1. Old customer data. Successful e-mail marketing relies on good, clean data. While you do need some critical mass to be successful with e-mail marketing, think quality, not quantity. Verify your customer preference data every six to 12 months and trim recipients who have become inactive or disinterested. Your list size may shrink, but the quality of your database will increase dramatically and so will your delivery rates.
  2. E-mail authentication. ISPs use authentication to identify a sender to more effectively protect their customers from spam. There are two forms of authentication: IP-based (SPF/Sender ID) and cryptographic-based (Domain Keys and DKIM). Either method will help improve deliverability of your e-mails, and combined they will work even better. If using an ESP, make sure it is using authentication when sending your messages. If hosting e-mail in-house, check with your system administrators to determine if your company is publishing authentication records.
  3. ISP rules. ISP rules, contacts, departments and processes change almost daily. As a result, it takes active industry involvement every day to make sure your e-mail is complying with the current best practices. If your company does not have a dedicated ISP liaison, find a partner or ESP that does.
  4. Subject line blunders. Ask yourself, “Does my subject line contain spam triggers?” This will help in getting the message delivered. Avoid special characters (such as dollar signs or percent signs) in your subject lines. These characters can cause messages to be viewed as spam. Additionally, steer clear of spam-catching words including: “free,” “you win,” “for a limited time,” “guaranteed,” “important message,” etc. Rewrite the subject line a few different ways to come up with the best approach and test the subject line through a spam filter-checking application prior to mailing.

Deliverability can be a laborious task if not properly addressed. By following ISP guidelines and best practices, your e-mail delivery rates can improve today.

Spencer Kollas is director of deliverability services for Premiere Global Services (, an outsource provider of business process solutions.

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