How Changing 1 Sentence Led to a 42 Percent Increase in Revenue

My team and I were doing all of the online donor-acquisition work with the George W. Bush Presidential Center. In our very first test, we made a very subtle change. The only difference appears in just one sentence — the very last sentence of the email. We ran the test. And check out the results — the new treatment, the one with revised sentence, generated a 139 percent increase in the clickthrough rate and a 42 percent increase in revenue.