In 2014, the Mobile Marketing Association launched a research initiative to help individual brands improve the efficacy of their mobile-marketing efforts. Each case study addresses marketers’ core questions in a unique way: What share of their overall advertising spend should be allocated to mobile marketing? How should they use mobile formats and targeting methods more efficiently to maximize the performance of their media investments? Although the authors acknowledge that their findings “might not provide definitive answers of long-term effect for all marketers,” they do offer insight into how mobile marketing can be optimized on a case-by-case basis. In 2017, campaign case studies with Allstate Insurance and a major U.S. fast-food, or quick service restaurant (QSR), chain were the latest additions to a body of work with AT&T, the Coca-Cola Company, MasterCard, Walmart, and Unilever. The most striking results came from the QSR study, which estimated an optimal allocation to mobile for that campaign at 33 percent of the total media mix—the highest allocation ever recommended in this research program. In the pages that follow, the authors describe their methods and findings, and propose best practices and questions for future research.