This lesson covers the most important metrics to monitor — Click-Through Rate (CTR, how often a thumbnail gets clicked when shown), Average View Duration and Audience Retention (how much of a video people actually watch), and Impressions (how often your video was shown to potential viewers). It covers what generally strong benchmarks look like for these metrics, and why a video with high impressions but low CTR usually points to a weak thumbnail or title, not a content problem.