At some point in history when the British ruled India, the colonial government were concerned about the number of venomous cobras. No one likes to be bitten by a poisonous snake, right? They decided to put a bounty on every dead cobra. Intended effect was that people would capture and kill the snakes reducing the population of cobras. However, another thing happened. People started to breed cobras intentionally, so they could kill them and receive the bounty. When the colonists learned about this, they stopped the reward program. Now with the cobra’s not having any value the breeders released them. Oops, the initial problem even became a larger problem.
This mechanism is called the cobra effect and there are many examples that show the same behaviour. Remember Hacktoberfest? An initiative to get people involved with Open Source by providing a T-Shirt for their initial contribution. Result? A vast number of useless contributions were being pushed to open-source projects overloading the maintainers. Goodhart’s Law describes it as “When a measure becomes a target, it ceases to be a good measure”. Small side note, this is not the original Goodhart’s Law, but a generalisation by Marilyn Strathern.