This document discusses the limitations of current attribution models and proposes a new "split funnel" attribution model. It notes that current models reward correlation over causation and do not differentiate between upper-funnel prospecting and lower-funnel retargeting activities. The proposed split funnel model divides the customer journey into prospecting and retargeting phases, and allocates credit separately for each phase to better reflect the roles of different marketing partners over the full customer journey. Key takeaways are to understand your funnel metrics and dynamics, and use split funnel attribution to set incentives that maximize desired results and outcomes.