How can I estimate the value of earned media coverage to show sponsors in my proof of performance report?

For print magazine coverage, start with the advertising rate card value for equivalent space (e.g., a full-page ad costs $4,000). Then apply a multiplier of 2-3x because editorial coverage from an authentic source is worth more than paid advertising. Factor in digital distribution - the same content gets shared on websites, social media, and email newsletters, multiplying the audience significantly. For example, a magazine with 350,000 Facebook followers and 130,000 Instagram followers dramatically extends the reach beyond print subscribers. Document all media appearances and calculate cumulative value across all channels to demonstrate ROI to sponsors.