This is from Josh Hendrickson at The Everyday Economist:
On Prediction: Suppose that you are a parent of a young child. Every night you give your child a glass of milk with their dinner. When your child is very young, they have a lid on their cup to prevent it from spilling. However, there comes a time when you let them drink without the lid. The absence of a lid presents a possible problem: spilled milk. Initially there is not much you can do to prevent milk from being spilled. However, over time, you begin to notice things that predict when the milk is going to be spilled. For example, certain placements of the cup on the table might make it more likely that the milk is spilled. Similarly, when your child reaches across the table, this also increases the likelihood of spilled milk. The fact that you are able to notice these “risk factors” means that, over time, you will be able to limit the number of times milk is spilled. You begin to move the cup away from troublesome spots before the spill. You institute a rule that the child is not allowed to reach across the table to get something they want. By doing so, the spills become less frequent. You might even get so good at predicting when the milk will spill and preventing it from happening that when it does happen, you and your spouse might argue about it. In fact, with the benefit of hindsight, one of you might say to the other “how did you not see that the milk was going to spill?”
Now suppose that there was an outside observer who studied the spilling of milk at your house. They are tasked with difficult questions: How good are you at successfully predicting when milk is spilled? Were any of your methods to prevent spilling actually successful? ...
Posted by Mark Thoma on Monday, January 29, 2018 at 11:09 AM in Econometrics, Economics, Macroeconomics |
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