The criteria and metrics can be classified according to its type and time span. Regarding the type, we can either evaluate these campaigns "Quantitatively" or "Qualitatively". Quantitative metrics may include "Sales Volume" and "Revenue Increase/Decrease". While qualitative metrics may include the enhanced "Brand awareness, image and health" as well as the "relationship with the customers".
SEO today is in many ways still a focused and specific discipline requiring experience and expertise. However, it has become much more dependent on, and integrated with, other digital marketing channels which is a good thing allowing for the scaling of content and resources. As most marketing is now digital, SEO has a proper seat at the table and place as a lead organic traffic driver contributing to end business goals.