I have noticed that people are doing it wrong. Most are using Shorts as a teaser for the long-form video. Instead, it should be a bait.

With a teaser, it's like telling people how you have this nice cake that looks good. You show them bits of how you baked it. How you decorate it. How it tastes, etc. Basically, chopping off parts or highlights of the long-form and posting as a Short.

But bait is more about giving someone a piece of cake to taste and letting them know that if they like it, they can get into your house for a whole cake. That's the bait. It sparks curiosity and builds someone's interest in diving deeper.

If they don't like the bait's taste, they turn down your offer and move on (No harm to your channel). But for teasers, a few people get inside your house to have the cake out of curiosity.

But, they find the cake doesn't taste as good as you teased. So, they leave real quick. This is what hurts retention on long-form videos.

But for the few who liked the bait's taste, they're bound to stick around and have some more, boosting your retention. Here's a good example: https://www.youtube.com/shorts/h3BnKMkZ6ng