PLAIN-LANGUAGE DEFINITION
CPA
CPA is spend divided by the number of attributed actions, such as purchases.
IN PRACTICE
An example
Spend of 500 and 25 attributed orders gives a purchase CPA of 20.
What this does not tell you
Name the action and attribution window; CPA alone does not establish profitability.
Use the term precisely
When you use this term in a brief or report, include the relevant source, scope and assumptions. An example explains the concept; it is not a benchmark or a promise of results.