The fragmented media landscape makes accurate attribution of successful marketing efforts increasingly difficult. As a result, marketing leaders are under greater pressure than ever to bring accountability to their entire marketing spend. Marketing mix modeling is a valuable tool for marketers to measure the effectiveness of marketing spending and track return on investment (ROI) across every dollar spent. CMOs and senior marketers need to work with a modeling vendor, their media agencies, and their own internal analytics teams to build accurate marketing mix models to drive efficiency and accountability for all marketing programs.