CPA stands for Cost Per Action (also sometimes referred to as Cost Per Acquisition).

RPA stands for Revenue Per Action.

As you might have guessed, this is the backbone of the CPA-based advertising model, where the advertiser determines how much every conversion is worth. In this case, a conversion can be a click, a lead, a sale, and so on…

For instance, let’s say that your ad was clicked 500 times and that you were paid $1 for each click (Don’t get too excited, this example isn’t very realistic in the real world!).

In this example, the provider is reporting that you made $500 in new revenue. The CPA is calculated by dividing this number by the number of conversions (“sales” for example) generated.

For additional terminology and key performance indicators for measuring success, please see:

All About Media Buying – Part 2 – Traffic Monetization