When measuring engagement, there are many tools and metrics to consider, depending on the type and format of your media content and ads. Reach is the number of unique users or households exposed to your media content or ads within a given period, while frequency is the average number of times that your media content or ads are viewed or heard. Additionally, time spent is the average duration that your audience spends consuming or interacting with your media content or ads, and engagement rate is the percentage of your audience that engages with your media content or ads by clicking, liking, sharing, commenting, or performing other actions. Retention rate is the percentage of your audience that returns to consume or interact with your media content or ads over time. To collect and analyze these metrics, you can use web analytics, social media analytics, email marketing software, video analytics, podcast analytics, radio ratings, TV ratings, and more.