Email Marketing Analytics: Calculating Percent Change – Free Worksheet!

Running split tests on your email list is the key to creating effective email marketing campaigns. You always have to be testing! However, what do you do with all those numbers after you’ve run your tests? How do you determine if something was effective or not? Looking at two simple percents, you might think that a subject line split didn’t yield statistically significant results if the open rates were 10% and 11%. A one percentage difference isn’t much, right? Wrong.

The one thing people get wrong all the time when looking at email analytics is percent change. Since most of us aren’t math majors (guilty!), it’s easy to make this mistake. Unfortunately, simple subtraction isn’t how you find the difference in percentages. That comes with the percent change formula.

The formula works like this: ((y2 – y1) / y1)*100 = your percentage change. Y1(1st Value) Y2(2nd Value). Looking at the example above, we would take ((11-10))/10*100 to get 10%. The percent difference between these two open rates wasn’t 1% after all, it was a whopping 10%! Since anything over 5% is considered statistically significant (meaning you can take action on this data), you would absolutely consider the 11% open rate a winner.

See? More complicated than you thought, but still not that complicated. Basically, you’ve been making your email marketing decisions on incorrect data. So let’s fix that!