nly known as the QWERTY keyboard) and the triumph of VHS over Beta as the leading format for video cassettes. The lack of systematic evaluation has allowed the proponents of network exter- nality theories to be somewhat imprecise about what constitutes lock-in. The absence of a clear definition of terms ignores the fact that no technological standard is permanent and that over a long enough time horizon all technological standards are subject to change. Whether a technology has become locked in is thus in no small part a function of the period of time deemed relevant for evaluating such a change. The failure to explain terms essentially renders the concept of lock-in currently employed in the literature arbitrary and obscures any attempt to prove or falsify its existence empirically. Furthermore, close analysis of the historical record reveals that none the key examples that form the empirical basis for network externality theory can properly be regarded as market failures. Specifically, the evidence suggests that the QWERTY keyboard does not represent an obsolete technology locked into place by network externalities. On the contrary, it appears that the QWERTY keyboard first emerged as the winner of a vibrant competition on the merits, in which various keyboard designs were tested against one another in a series of typing contests. In addition, the evidence supposedly demonstrating the Dvorak keyboard's superiority is riddled with conflicts of interest, because all of the key studies, including the Navy tests that represent perhaps the primary support for these claims, were conducted by the person who invented and patented the Dvorak keyboard. Modern ergonomic studies suggest that any technical difference between the QWERTY and the Dvorak keyboards remains nominal at best (Liebowitz and Margolis 2001). The historical record also contradicts the suggestion that VHS's emergence as the prevailing standard for videocassettes represents the perseverance of an obsolete technology. Any suggestion that VHS's victory was