What mechanism does Google Ads use to determine which ads are displayed?

The mechanism used by Google Ads to determine which ads are displayed is primarily based on a bidding process that considers both the bid amount and the Quality Score. This system is designed to ensure that the most relevant and high-quality ads appear to users while balancing ad placements with revenue considerations.

Quality Score is a critical component in this process, as it reflects the relevance of the ad to the user's search query, the expected click-through rate (CTR), and the quality of the landing page. A higher Quality Score can lower the cost-per-click (CPC) that an advertiser pays, potentially allowing ads to rank higher even if the bid is lower compared to other advertisers.

Bid amount alone is not the sole determinant; without considering ad quality, irrelevant or low-quality ads could monopolize ad placements, resulting in a poor user experience. The combination of these elements creates an auction-driven environment where the most effective ads are showcased in response to user queries, fostering a competitive advertising ecosystem.