Most business owners focus on the core cost metrics of their ads rather than the conversion metrics. Yes, CPM, CPC, CPA, CPL, CPP, and CTR are all vital in determining whether your investment was worth it or not… 

As a seasoned affiliate marketer and copywriter, however, I would recommend prioritizing CR, AOV, and ROAS. They are the clearest proof of whether your ad was a success or not. 

Back when I was working with an Amazon affiliate marketing agency, our motivation was the famous “Jobs to Be Done” framework. 

The next time you run an ad, consider that the majority of people make a purchase because they believe that thing will mean something to them. The “meaning” could be emotional (the product gives them a special feeling or creates a special memory), transformational (the product gets them where they want to be), or identifiable (they want to be associated with the product).