Leading indicator

Some numbers tell you what already happened and some tell you what is about to. Subscriber count and revenue are settled facts by the time you read them. Click-through rate in the first hours, or the shape of the retention curve on a fresh upload, move earlier and point at where views will end up, which is what makes them worth checking daily. Promoting one to a target is where this goes wrong. Optimise hard for an early metric on its own and you can make it climb while the outcome it was supposed to predict stays flat, which is how channels end up with plenty of clicks and no watch time.