Incentives refer to the rewards that people have for certain behaviors. It is a powerful tool to change people’s behaviour. For example, in order to deal with the increasing number of students drops out in the middle of university, the university offers 15% of their tuition back if students graduate. On the other hand, perverse incentives refer to something that gives people an incentive to do something undesirable. Florida’s three strikes law in 1994 would be an example of perverse incentives. The law states that if a person already commits 2 serious crime, then he or she will be sentenced to 25 years in prison when committing the third crime whether the crime is severe or just a small one. Its purpose is to stop people from committing crime after crime, and it seems to be a successful law. However, the number of police officers who died doubles since this law had introduced. Criminals take advantage of this law which they would tend to kill someone since they would get the sentence of murder just the same as the sentence for a robbery. Similarly, death sentence can only have perverse incentive when criminals may commit a crime when they know they will be hung anyways. The study of economics is the study of incentives and how people response to choices to get the best results for themselves. People are not naive to respond to choices predictable. In fact, people make choices that gives them a good result not burden, and those choices can harm others.