Which is the main performance indicator for campaigns?

ACOS (Advertising Cost of Sales) is the primary performance indicator for Mercado Ads campaigns because it directly measures the efficiency of ad spend in generating sales. It's calculated by dividing total ad spend by total sales revenue from ads, then multiplying by 100 to get a percentage. A lower ACOS indicates a more profitable campaign. While CPS (Cost Per Sale) is related, ACOS provides a more holistic view by considering the total sales generated, not just the cost of individual sales. CPC (Cost Per Click) is a metric for engagement, not direct sales performance. Revenue/day and Total revenue are important for overall business health but don't specifically measure the efficiency of ad spend.