The cliff effect is like when you are climbing up a hill, and suddenly, the road becomes steep, and you can't climb any further so you fall off the edge. In the same way, when someone is getting help from the government, like food stamps, childcare, and housing assistance, they might reach a point where they earn a little more money, and suddenly, they lose all the government benefits, and their income drops below the poverty line. It's like they fall off the edge of the cliff.
For example, let's say your mom gets food stamps to buy groceries for you and your family. She also gets help paying for childcare so she can work. Your mom earns a little more money, and suddenly, she loses all the government help. She has to pay for food and childcare all on her own, which costs more money than she makes, but she can't get government help because she earned too much money. So, she has to stop working or choose between paying for food or childcare.
The cliff effect can make it challenging for families to get out of poverty, even when they work hard and earn more money. It is because when they lose the government assistance, they can't afford basic necessities like food and shelter. That's why some people say we need to change the system to help families gradually reduce their dependence on government help so they can climb the hill towards success without falling off the edge of the cliff.