It is well known that the Nash Equilibrium means that players will not better off by deviating from the equilibrium. If some irrational player deviates, its cost may increase. I am wondering does there exist a numerical description of the cost change between the strategy to cost change. For example, in two different games, in the first game, if the player deviates, its cost increases by 10. But in the second game, its cost increases by 20. Does this mean the first game is more robust or insensitive to deviations?
Thanks