Persado Study Finds E-Mail Subject Line Length Does Not Impact Performance


September 27, 2016 – NEW YORK, NY – Persado, the leading cognitive content generation platform, today announced the results of a comprehensive e-mail subject line length and performance analysis. The results of correlation tests show that, contrary to popular notion, character count has no real bearing on subject line effectiveness.

Persado examined more than 20,000 subject lines from its cognitive content database, a growing collection of over one million tagged words, phrases, and images continuously scored against marketing performance. Those subject lines were tested on a normal sample size, with an average open rate of 13.3 percent and an average click through rate of 1 percent. The test was implemented across groups with 0-59 characters, 60-73 characters, 74-88 characters, and 89-206 characters in the subject line. In every case, the correlation test showed that there was little correlation between subject line length and click through or open rate.

The data was also evaluated across industry verticals. Examining the retail & e-commerce, financial & insurance services, telecommunications, and travel & hospitality sectors individually, the analysis showed very weak or no correlation between response rates and the length of e-mail subject line. The comprehensive analysis is available on the Persado Insights blog.

“Persado’s cognitive content platform empowers marketers to make creative decisions that are driven by data, instead of ‘best practices’ that are often anything but,” said Alex Vratskides, Co-Founder and CEO of Persado. “This analysis debunks the prevailing, unsubstantiated belief that shorter subject lines are better. Instead of length, marketers need to focus on delivering content that has personal and emotional relevance to the consumer to effectively inspire action.”