Patent Protection and Strategic Delays in Technology Development : Implications for Economic Growth

We present an endogenous growth model in which both the investment to develop a new technology-that upgrades the quality of machines-and entry of imitators are determined endogenously. According to the model, how soon the new-technology machine is launched after the patent is granted is influenced by two factors: returns to scale in technology development and "strategic delays." Strategic delays in technology development are most likely to occur when earlier dates of success enable imitators to enter an industry, i.e., when imitation is swift and relatively cheap and/or patent protection is relatively lengthy. We then explore the link between the optimal patent length and economic growth, and find that the equilibrium investment in technology development and thus the expected rate of technological progress exhibit an inverted U-shape relationship with respect to the legal patent length. Our results further suggest that, in order to minimize the strategic delays in technology development and spur technological progress, legal patent lengths should be shorter in industries where barriers to entry are relatively low