An investor who year in and year out who is usually in the red.
What might be the reasons to explain their different outcomes?
Is this entirely a question of superior selection of stocks? Maybe NOT entirely.
Is this entirely a question of superior timing of buying and selling of stocks? Maybe NOT entirely.
How good are economists in their forecasts?
In a meeting of economists, they agreed if their forecasts were 1/3 correct, that was considered a high mark in their profession.
You cannot invest in securities successfully with odds like that against you if you place dependence solely upon judgement as to the right securities to own and the right time or price to buy them.
It is also a case of knowing how to capitalize successes and curtail failures.
You have to learn by doing.