you compare the derivative yesterday, you measure the derivative today. difference between them is the jerk. It tells you where you are on the S-curve

It's only in retrospect that you know the level of filtering required to find this S curve trend among the noisy perturbations.

Just like people trying to time the market with "technical analysis". It is extremely easy to find whatever pattern you are looking for. A lot harder to accurately distinguish predictive power from fantasy.