Beyond sourcing new demand, marketing must more precisely define and measure its contribution to the revenue engine. A lack of specificity in metrics about their influence on successful deals can rouse skepticism among key audiences rather than building understanding and an increased willingness to collaborate. By precisely establishing how, when and with whom influence is delivered, marketing can more effectively identify its impact, and tailor its focus and resources accordingly. In this report, we provide guidelines for a more credible data-backed approach to identifying and measuring marketing's influence.