Essential to any market economy. To trade, it is essential to know that the person selling a good or service owns it and that ownership will pass to the buyer. The stronger and clearer property rights are, the more likely it is that trade will take place and that prices will be efficient. If there are no property rights over something there can be severe consequences. A solution to the costly externality of clean air being polluted may be to establish property rights over the air, so that the owner can charge the polluter to pump smoke into the atmosphere. Private property rights are often more economically efficient than common ownership. When people do not own something directly, they may have little incentive to look after it. (See the tragedy of the commons. ) Strikingly, in Russia after communism, the establishment of a well-functioning market economy proved difficult, partly because it was unclear who owned many of the country’s resources, and those property rights that did exist often counted for little. Businesses would often have their products stolen by criminal gangs or be forced to hand over most of their profits in protection money. It is no coincidence that an effective judicial system, as well as property rights for it to enforce, is a feature of all advanced market economies. That said, nowhere are property rights absolute. For instance, taxation is a clear example of the state infringing taxpayers’ ownership of their money. The economic cost of infringing property rights underlines how important it is that governments think carefully about the consequences for economic growth of their tax policies.