Goodhart's Law is one of those neat formulations that codifies something I've been trying to put my finger on for years: "once a social or economic indicator or other surrogate measure is made a target for the purpose of conducting social or economic policy, then it will lose the information content that would qualify it to play such a role."
That is, once you start measuring GDP as a way of gauging social welfare, people will start to figure out ways to make GDP go up without improving social welfare (say, by swapping dirty financial derivatives). Once Google starts measuring inbound links as a way of evaluating the importance of web-pages, people will figure out how to increase the inbound links to unimportant pages (splogging, blogspam). And once you measure fat or calorie content as a proxy for the healthfulness of food, manufacturers will figure out how to decrease fat and calories without making the food more healthful (reducing fat by adding sugar, reducing calories by adding poisonous artificial sweeteners).
The law was first stated in a 1975 paper by Goodhart and gained popularity in the context of the attempt by the United Kingdom government of Margaret Thatcher to conduct monetary policy on the basis of targets for broad and narrow money, but the idea is considerably older. It is implicit in the economic idea of rational expectations. While it originated in the context of market responses the Law has profound implications for the selection of high-level targets in organisations.
It’s not just Mexican cement giant Cemex that’s refusing to bid on the Great Wall of Trump; many of the firms in the super-concentrated large-scale construction sector are signalling their unwillingness to participate in the wall’s construction.
In 2012, Google rolled out Certificate Transparency, a clever system to spot corrupt “Certificate Authorities,” the entities who hand out the cryptographic certificates that secure the web. If Certificate Authorities fail to do their jobs, they put the entire electronic realm in danger — bad certificates could allow anything from eavesdropping on financial transactions to […]
With the shambolic FARC peace deal finally in place, the Colombian government is hoping to shift the country’s farmers from Colombia’s major cash crop: the coca leaves that are refined into the world’s cocaine supply. Perhaps with the guerrillas no longer defending the crops they relied on for operating capital, Colombia can put coca behind […]
What could be more fun than a slingshot that shoots tiny airplanes? A slingshot that shoots tiny glowing airplanes of course! These toy planes are outfitted with ultra-bright LEDs, so you can fly all night without losing them in the trees.Whether you are a regular-sized child, or an overgrown adult one, these light-up flyers offer […]
You know the drill. You go to the dentist and they ask you how often you floss. You lie through your teeth and say, “every day!” (Bonus points if you have some cilantro or chives stuck in your gums from lunch). You don’t want to keep up the charade any longer, but rubbing that tiny strand […]
The Raspberry Pi Foundation has done outstanding work packing a fully capable desktop computer into a package the size of a deck cards—especially one that only costs $35. But if you already have a working laptop, why should you care? Oh, how much you have to learn. Besides operating well as a compact digital media hub, […]