Return on ad spend (ROAS) is not the most important metric to pay attention to, when measuring PPC advertising success. ROAS is secondary! Steve explains why in this 3-minute video.
The most important PPC metric is adverting cash flow, which is simply the revenue generated by campaign(s) minus the ad spend used to generate the revenue. It is calculated from the same two variables used to calculate return on ad spend (ROAS). The difference is that ad margin is calculated by subtracting cost from revenue, will ROAS is calculated by dividing cost into revenue.