A/B subject line split testing is one of the smartest and easiest techniques marketers can use to accelerate response. Since email marketing is instantaneous, unlike traditional postal mail, you gain the added advantage of receiving statistically valid results within just a few hours.
To split test your campaign, extract 20 percent of your list as a test group. Then split this sub-group into two: Group A and Group B. Send a test campaign using two unique subject lines to each group. Then, within just three hours, you should have enough data compiled to analyze results and determine which headline reaped the greatest response. While this practice works best with large lists of more than 1,000 recipients, you should still acquire worthwhile feedback with smaller lists.
When marketers test and tune their email subject lines, they can improve response rates up to 42% on average. Reports are immediately available, so they can change a subject line, body content, layout or design on the fly. The extra time devoted to testing and fine-tuning a campaign will increase reader satisfaction and loyalty.