Retail marketers' understanding of radio and television advertising campaigns' impact on retail store visits would be a major breakthrough in evaluating return on media investment. This article presents results from pilot research using Arbitron's Portable People Meter (PPMSM, a mark of Arbitron Inc.)—a unique audience measurement system that enables radio, broadcast television and cable television usage, and retail store visits to be captured from a single-source national panel of consumers. The pilot research indicates that retail store visits correlated with media advertising exposure, illustrating the promise of a single-source research panel to measure ROI in terms of store visit behavior, an important driver of retailer financial results.