The 2 x 2 matrix game plays a central role in the teaching and exposition of game theory. It is also the source of much experimentation and research in political science, social psychology, biology and other disciplines. This brief paper is addressed to answering one intuitively simple question without going into the many subtle qualiﬁcations that are there. How eﬀicient is the non-cooperative equilibrium? This is part of a series of several papers that address many of the qualiﬁcations concerning the uses of the 2 x 2 matrix games.