Improving through comparison.
WHAT A TEST IS
Sending two versions to portions of your list and comparing.
WHEN IT IS WORTH DOING
When your list is large enough for the difference to mean something.
For a list of two hundred, the difference between two subject lines is noise. Do not bother.
WHAT TO TEST
Subject lines, most commonly The call to action wording Content length or format
ONE THING AT A TIME
Testing two things simultaneously tells you nothing about which caused the difference.
WHAT TO DO WITH THE RESULT
Apply it to the next campaign. A test that changes nothing was wasted effort.
Record what you learned; otherwise you test the same thing repeatedly.
FOR SMALL LISTS
Instead of formal testing, vary your approach over several campaigns and watch the trend.
Less rigorous and more practical at small scale.
WHAT NOT TO CONCLUDE
That one campaign's result establishes a rule. Content differs, timing differs, and the audience mood differs.
Patterns over many sends mean something. Single results do not.
