By John Landsman, Director of Strategy and Analytics

This is our third excursion into the matter of subject lines, because there is little of greater importance than subject lines in deploying email that works.  All the brilliance contained within actual email content is lost if the email doesn’t ever get opened.  And subject lines are — along with mobile optimization and effective targeting — key factors in driving email opens.

Because so much commercial email is deployed to support price-off promotional activity, subject lines are often also festooned with incentive language, sometimes to the exclusion of everything else.  eDataSource can see the subject lines of those emails, and how customers engage with them.   And that’s our story today.

What We See And What It Tells Us

When we analyze retail email for our clients, we filter subject lines for certain incentive-type keywords.   Usually those keywords are, “Save,” “Dollars,” “Percents,” “Free-Shipping” and “Exclusive.”  

Not surprisingly, usage varies by retailer and occasion, but in the pattern we most often see, “Save” type incentives are typically the most frequently used across brands, and also the most extensively as a percentage of a brand’s total promotional email activity.  “Percents” also appear, although somewhat less frequently, and “Dollars” less frequently than that.  “Exclusive” is used, but not heavily.  “Free-Shipping” appears less often than one would expect, although those offers do appear much more reliably within email body content, irrespective of what their subject lines say.  

Where this excursion gets really interesting is where we look for common email open patterns connected with each of these incentive-type subject line keywords.   And we don’t see those patterns happening.  

Within any given incentive type, open rates vary; i.e., no incentive’s open rate consistently outperforms any other.  Not only do open rates vary within any incentive type, their variability extends to their relationship with the respective brand’s overall open rates for the time-period in which the email is deployed and tracked.  That is, the open rates associated with a given incentive type are also not consistently higher than the brand’s overall email open rates for that period.  

Does that mean that these incentives aren’t worth using, or featuring in subject lines?  Of course not.  But it does mean that we might want to look beyond using just incentive language as drivers of subject line content.

When we analyze some of the top-performing client emails — by which we mean from among a brand’s top-five open rates for a given period, rates that strongly outperform that brand’s period open rates — we do not always see just incentive language in their subject lines.  Examples:

  • “Incredible prices on coats, sweaters and more.”  (Macy’s)


  • “Textured bucket bags for her, from Vince Camuto.”  (Nordstrom)
  • “Get ready for back-to-school with the write stuff & free shipping.”  (Oriental Trading Company)
  • Descendants costumes are here.”  (Party City)
  • “We’ve waited all year for this.”  (LongHorn Steakhouse)
  • “The tastiest email you’ll open all day.”  (Outback Steakhouse)
  • “Fall 2015 Collection:  Now in-store and online.”  (Coach)
  • “The power of the patterned t-shirt.”  (Tory Burch)


Our point is that effective subject lines can and should use language that is both informative and stimulates a desire to pursue what’s in the message.   Just blaring headlines limited to price-off language is no guarantee of success, and in fact may be conditioning customers to respond only to price concessions.   Product references that are personalized to specific targeted customer segments are also often success-drivers, as are certain elements of humor, mystery and time-sensitivity.

As in so much we talk about, this is a matter for controlled testing.  There’s no downside here; only possible gain.  Just think of what only one or two incremental open rate points may be worth.


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