INSTAGRAM EXPLAINS HOW ITS ALGORITHM WEIGHS TIME SPENT WATCHING LONGER CLIPS

Summary from the TLDR Marketing newsletter

Instagram's algorithm measures watch time as a percentage of the video but also considers the total seconds watched, ensuring longer videos aren't penalized. Watching a portion of a longer video counts the same as watching that portion of a shorter video. This approach prevents creators from being disadvantaged by longer clips, even if they don't achieve high completion rates. Instagram encourages longer content to boost engagement, especially with the recent expansion of Reels to 3 minutes.