Policy ineffectiveness proposition

Okay, so you know when your mommy tells you to clean up your room, right? Now, imagine that your mommy is the government and she's telling the economy what to do. Sometimes the government wants the economy to do something, like grow bigger or not have too much inflation (that's when prices go up too much and we can't afford to buy things).

The policy ineffectiveness proposition is a fancy way of saying that sometimes, when the government tries to tell the economy what to do, it doesn't work out the way they thought it would. Just like how sometimes when your mommy tells you to clean up your room, it doesn't actually get clean - maybe you miss a toy or you don't put your clothes away the way she wants you to.

So, the idea is that even if the government makes a rule or a policy, it might not work out the way they wanted it to. For example, they might try to lower interest rates (that's like how much it costs to borrow money) to encourage people to spend more money and help the economy grow. But sometimes it doesn't work - maybe people are too worried that the economy is going to get worse, so they don't want to spend more money anyway, even if it's cheaper to borrow.

So, the policy ineffectiveness proposition is just a way of saying that sometimes the government tries to help the economy, but it doesn't work the way they thought it would, and they have to try something else.