A more thorough explanation:

Definition: Proportionality review is a process in criminal law where an appellate court examines whether a death sentence is arbitrary, capricious, or excessive. This is done by comparing the case in which the death sentence was imposed with similar cases in which the death penalty was either approved or disapproved.

Example: Let's say a person is convicted of murder and sentenced to death. The appellate court will then conduct a proportionality review to determine if the death sentence is appropriate. They will look at similar cases where the death penalty was either approved or disapproved to see if the sentence in this case is consistent with those decisions.

Explanation: Proportionality review is a way to ensure that the death penalty is not being arbitrarily or excessively applied. By comparing the case in question with similar cases, the court can determine if the sentence is consistent with previous decisions. This helps to ensure that the punishment fits the crime and that the defendant is not being unfairly punished.