Email Deliverability Tested: How “FREE” produced a 6.7% higher clickthrough rate
Most marketers are afraid to use the word “FREE” (especially in all caps) in their emails because they’ve heard it tends to trigger spam filters. When that happens, it’s generally a bad thing as less of your emails get read. No emails getting read means no offers being viewed. That’s BAD. Right?
Well as the Junior Editorial Analyst here at MECLABS, MarketingExperiments’ parent company, I’m charged with sending out emails to our MarketingExperiments list of about 100,000 marketers around the globe. That means I also get to test just about anything I want in an email to probably most of the people reading this blog post.
Because of the hot debate around this issue, I knew I wanted to test the word “FREE” in an email to see what it did.
It turns out, the word “FREE” in the body of my Web clinic email [could have (see comments below)] hurt deliverability by 6.6%. But despite a higher bounce rate, I still got a higher clickthrough rate.
Here’s the deliverability statistics on the two emails:
The Bounce Rate Results:
What you need to understand: PART 1
In this case, it would appear that using the word “FREE” in the body of an email can hurt your deliverability. But also in this case, deliverability isn’t our main KPI—it’s clickthrough rate.
With that in mind, I examined the results of the clickthrough rate compared to the total sends.
The Clickthrough rate results
What you need to understand: PART 2
When I measured the clickthrough rate against the total attempted sends, I still got a 6.7% increase in total clicks. In other words, taking into account the number of bounces the word “FREE” caused, email treatment B still won by a statistically significant margin.
How to test “spammy” words in your own emails
We already know that clarity trumps persuasion. What we didn’t know was that clarity trumps even email deliverability. According to this test, it would seem that simply stating that the Web clinic was free and being a little more specific in our wording about what was on the other side of the click, we got better results than when we tried to avoid the word “FREE.”
However, just because it worked for the MarketingExperiments audience doesn’t necessarily mean it will work for yours. Here’s a few tips for testing “spammy” words in your own email campaigns.
- Always be clear. Don’t just test words like “free” because you heard on this blog that you can get a higher click-through-rate with it. Be clear first. If there is a clearer way to say something without saying “free,” say it.
- Make sure your results are valid. With smaller margins of difference, you could be making a big mistake assuming your numbers are statistically significant when they aren’t. Rule out other validity threats as well.
- Measure the clickthrough rate and the bounce rate relative to the total number of attempted sends. This one seems like a no-brainer but I almost made the same mistake myself when I was crunching the numbers. You’d be surprised how silly mistakes like this can totally ruin your view of a test.
What’s your experience with “spammy” words in emails? Do you find they help more than they hurt? Vice versa? Tell us about it in the comments…