• by Jess Nelson , December 27, 2016

A typo is the bane of any writer’s existence, but it can be especially problematic for email marketers, according to a recent study by Boomerang. 

The email services company analyzed more than a quarter of a million emails to investigate whether there was any correlation between errors in email subject lines and engagement rates. They passed the subject lines through an automated spell and grammar checker, similar to the one available in Microsoft Word.

Email response rates decrease as the number of errors in an email subject line increase, according to Boomerang’s study. Overall, emails without any subject line errors averaged a response rate of 34%. If an error was detected, however, the response rate average dropped to 29%.

Capitalization errors affected response rates by as much as 15%, according to the study. A correctly capitalized subject line averaged a response rate of 32.6%, but a subject line that began with a lowercase letter averaged a response rate of 28.4%.

Apparently, email marketers often have a bad "case of the Mondays" as the first day of the work week ranked as the most error-prone. Emails sent on Saturdays and Sundays were shown to have the fewest errors, but that might likely also be due to the fact that fewer emails are sent over the weekend. Friday was the second-most error-filled day for email marketers, while Tuesday ranked as the best workday to send emails.

Emails sent on Mondays also ranked as the least positive in terms of subject-line sentiment. This was a dramatic shift from Sunday, the day that accrued the most positive sentiment in email subject lines.