Analyzing online search relevance metrics involves understanding how well a search experience satisfies a user's information needs by examining various user interactions and behaviors. This process starts with capturing events like queries, page views, and clicks from users interacting with a search application and ingesting these events into Elasticsearch. Once collected, these events are transformed into per-query relevance metrics, which can be aggregated over time to provide insights such as click-through rates and query distribution. The Elastic Stack tools, including Kibana and Elasticsearch, assist in visualizing and managing these metrics, allowing for fine-tuning and improving search relevance. While metrics are helpful, they carry biases and require additional sophisticated tools for deeper analysis, like A/B testing. The post encourages further exploration and customization of metrics while discussing the potential challenges and limitations of using real user behavior as a basis for measuring search relevance.