Do you consider action of a person as a proof of his ability?

This is possible in some cases but I know some people who are really very good at something but do not show their abilities in action because of insecurity. THere are also people who seem to be so good in action for some period of time but eventually end up proving that their actions have been all for show and they are no good after all.

No i don't think that ability of a person's action is not a measurable unit for his proof of ability but what i believe is that action tendency of a man without any reason shows that man's bad nature