Most punctuation marks have almost no influence on open rates, except for one…sorta.

Punctuation marks. Sometimes we get excited and use multiples, other times we make it a question. But overall, when looking across the board, what sort of impact does any one punctuation mark have on the open rate of a subject line? Here’s what we found.

The Goods
To find our answer we looked at email campaigns sent during the last 12 months to over 300,000,000 recipients. We then found the average open rate for messages that contained any one of six punctuation marks.

For this sample, quotation marks saw the highest open rate at 18.7% while question marks saw just a 17.9% open rate. The average open rate during this period was 19.0%. Emails in this sample that contained no punctuation marks averaged an open rate of 19.9%.

What This Means
First, while there is some fluctuation between various punctuation marks, there’s not much. From the best to the worst is a 0.8 percentage point gap. What’s interesting, however, is that ALL of these punctuated subject line averages sit below the overall average.

Now take a look at that last bar on the chart above. Not only does it represent subject lines that included no punctuation at all, it’s also the only one that’s above average.

Next Week, Another Post
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