There has been a great deal of talk about marketing attribution and how it can improve your results. Walk the floor of any marketing conference, and nearly every vendor now claims to do attribution. This has created a lot of noise and confusion in the marketplace. This paper explains what marketing attribution is and dispels many common misconceptions. It compares attribution to other analytics, and establishes where attribution fits in. It also contrasts media mix modeling and attribution and clarifies the differences. The paper, first published in May 2013, also provides guidance on the 5 key criteria to look for in an attribution vendor, to know if they will really improve your results. This guidance includes information on how to rank attribution systems against one another to assess their relative performance in the areas of compliance, completeness of the system, accuracy, potential impact on your results, and risk.