A media planner is running an awareness campaign for a drinkware company, using video, carousel, and quiz ads. The campaign targets second- and third-party audiences, but cost per mille (CPM) is higher than expected, raising concerns about budget efficiency. What tactic can help lower the overall CPM for the rest of the campaign?

Optimizing creative by focusing on the most cost-efficient ad format directly addresses high CPM. By identifying which ad formats (video, carousel, or quiz) deliver the lowest cost per thousand impressions, the planner can allocate more budget to those formats, thereby reducing the overall average CPM. Shortening the campaign duration might reduce total spend but won't inherently lower CPM. Continuing as-is without intervention will not resolve the current budget efficiency issue. Building a first-party audience is a good long-term strategy for engagement but won't immediately lower CPM for the current campaign and may even require additional investment to build and activate.