Undercover Economist

Dear Economist,
I am 22 years old with a younger sister. My parents were pretty strict, so I made sure I was a sensible teenager. I didn’t sleep around, didn’t take drugs, never seriously smoked and went on to a good graduate job. But now my 17-year-old sister is getting away with murder: my parents know she smokes, let her boyfriends stay overnight and turn a blind eye to other misdemeanours. It’s just not fair. Did I make a mistake in being such a square as a teenager?
Georgie H, Hertfordshire

Dear Georgie,

The latest Economic Journal presents a simple game-theory model of the problem. All teenagers wish to misbehave but fear parental sanctions. Parents wish to threaten punishment for transgressions, but only some parents are strict enough to do so. Your younger sister’s mere existence skewed the game to your disadvantage. Your parents are evidently soft-hearted, but had a clear incentive to pretend to be strict because every time they punished you, they knew they were also deterring your sister.

Now that you have flown the nest, the gains from “acting strict” are much smaller and discipline has slipped. Your sister pushed and discovered that they did not push back; you would not have found it so easy. But sunk costs are sunk costs, so be content with your graduate job. And if you really want to take drugs and sleep around, I can assure you it is not too late.

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