Which PPC Metric Is Most Important?

CPC. CPM. CTR. ROI. ROAS. Conversion Rate. With all these metrics, which one should you focus on? Which one is most important to understand?

Of course, the answer is somewhat subjective, depending, in part, upon your particular marketing plan and tastes. Furthermore, the answer may not be uniform across all marketing elements. Because I'm becoming an increasingly more "bottom line" guy, for me, the Cost Per Acquisition (CPA) is becoming all-important.

*What Is Cost Per Acquisition?
The definition of CPA is pretty straightforward: CPA is the amount of money you spend to acquire one customer or sale. The term is usually used in context of a PPC advertising campaign, wherein the the term means: the amount of money you spend in clicks (or conversions) to generate 1 sale or client.

In short, CPA is the "metric of the bottom line". In our consulting, we've found that this is what most clients really want to know, before we can sell them on the benefits of a PPC campaign. And it makes sense why. Knowing how much it will cost me in ad spend to get 1 customer makes it a snap to calculate the ROAS and ROI of the ad campaign and, thus, to determine whether a client can afford a PPC campaign at all.

CPA also can give insight on price setting, sometimes alerting a client to when he's charging too little or too much for a product or service. In this regard, CPA also helps more easily calculate a business' overall profitability, as the CPA can be directly subtracted from the overall revenue the business generates.