What is Retention?
Retention measures how far the person got into the content. For video, it is the percentage watched and the curve showing at which second the audience leaves; for a carousel, it is how many slides were seen. It is the signal that weighs most in Reels distribution: a video that holds until the end is shown to more people. A drop in the first three seconds points to a weak hook; a drop in the middle, to content that did not deliver what it promised. Improving retention starts with the hook and continues by cutting everything that does not move the story forward.