Subjective probability

There is little doubt that investing is all about expectations. It is also well known that expectation has a lot to do with probability. The expectation of having 90% upside with 10 points and 10% downside with 20 points is 7 points. The probability of 90% is different than tossing a coin to get a tail probability. Why not 80%? It is subjective to everyone's comprehension.

This is subjective probability in investment. How do we make subjective probability closer to the actual probability? Need to get more information and get investors trained. It is a learning process. So far, nothing is more interesting than noticing this fact:

Everyone can have their own subjective probability accessment. Now assuming there is a big pool of investors who have no problem in communicating with each other, they all submit their subjective probabilities and compare who do better. After comparison, they learn various things from the best ones such as how to analyze and evaluate probability and go on with the next rounds. Will they get convergence eventually in terms of subjective probability? This is analogous to learning in a class, at the beginning there are various thinkings but at the end of the class, students become more homegeneous.

But this is not true in the market. Good investors/traders don't have learn from each other freely and completely but just piece by piece. It could be million reasons why a subjective probability has been drawn. But it is necessary to learn as much as we can if opportunities are available.

So read just a few who have been studied completely to get a full picture.