In 2014, oven chip brand McCain was struggling. Cash-strapped shoppers were switching to cheaper brands and own label. Promotions were delivering short-term volume, but depressed revenue and margins. To reduce price elasticity, McCain committed to a sustained investment in brand advertising. But success took time and patience. Winner of the prestigious 2024 IPA Effectiveness Award Grand Prix for long-term growth, the nine year journey reduced price elasticity by 47%, raised base sales by 44% and delivered £26 million of net profit. We talk with Mark Hodge of McCain Foods and Roisin Mulroney of adam&eveDDB. Thanks to Tracksuit and the Master of Advertising Effectiveness Program (MAE) for sponsoring this effectiveness episode.