Emissions taxes and carbon caps can both lead to efficient production of energy, in the sense of controlling carbon emissions to the extent that is efficient with existing technologies. However, the regulatory policy has a second objective, which is to create incentives to develop lower-carbon...

Open source collaborations are increasingly among commercial firms whose interest is profit. Why would profit-motivated firms voluntarily share code? One reason is that cost reductions can outweigh increases in rivalry. This is especially persuasive when the contributors make complementary...

The patent system is mainly a renewal system: the patent life is chosen by the patentee in return for fees. I ask whether such a system can be justified by asymmetric information on costs and benefits of research. In such a model I show that renewal mechanisms (possibly with subsidies) are...

In active investment climates where firms sequentially improve each other's products, a patent can terminate either because it expires or because a noninfringing innovation displaces its product in the market. We define the length of time until one of these happens as the effective patent life,...