Prior to the advent of AI, creating multiple email subject lines took time and significant resources. However, AI content generation tools like ChatGPT, Copilot, and others now offer the possibility of creating not just one or two, but many subject lines in as little as seconds. This can provide email marketers with a wide range of new creative options. But are the resulting subject lines effective?
To determine the effectiveness of subject lines – whether created by AI or a human – you must test. Traditional A/B testing methods typically compare two or more subject lines using segments of your audience. This can be time consuming and costly in terms of wasting subscribers who receive emails with failing subject lines. We wanted to know how using AI to increase the volume of subject lines tested might impact opens and clicks.
The Analysis
To understand this, we conducted an analysis to determine the lift in email response when multiple subject lines were tested. Using Subject Line Pro, our virtual testing platform that delivers real results in seconds, we were able to analyze data from over 500 billion emails to discover the correlation between increases in open and click rates as the number of subject lines tested increased.
Our analysis showed that while testing 2 subject lines resulted in a 3% lift in opens and little or no lift in clicks, increasing the number of subject lines tested to 3 resulted in 21% more opens and 42% more clicks. That’s good news for marketers creating and testing just a few subject lines the traditional way. But what if AI was used to quickly and cost effectively generate 10 subject lines or more to test?
We discovered that by testing 10 subject lines, opens increased by 81% and clicks jumped by 242%. The click to open rate increased 128%. The chart below illustrates the lift in results as the number of subject lines tested increases from 2 to10.
Clearly the more subject lines you test, the bigger the lift in opens and clicks you can expect. Therefore, it stands to reason that using AI to quickly create ten or even a hundred subject lines could be very beneficial. However, as more subject lines are tested, time consuming traditional A/B testing could result in a bottle neck that negates the advantage of using AI. That is why we recommend Subject Line Pro.
Subject Line Pro enables you to test 10 subject lines at a time against a simulation of your own data or our database of more than half a billion subject lines across different sectors. It delivers accurate results in seconds. How accurate? Subject Line Pro’s proprietary algorithm predicts performance within 1 to 2% of actual clicks and opens.
We recently used Subject Line Pro to test 50 subject lines for a blog about testing last-minute campaigns. The entire process including entry of subject line text, testing against All Industry data, and generating results took less than five minutes.
The Take-Away
AI subject line generators offer exciting new creative options for email marketers. When combined with a virtual testing platform like Subject Line Pro, they can significantly reduce the time and expense of creating and testing subject lines, while dramatically increasing the lift in opens and clicks.
Want to know more about subject line testing? Check out The Golden Rule of Subject Line Testing.
