The ladder principle is used in bail court to help decide how much supervision you should have if you're released. The bottom of the ladder is the least amount of supervison and the top of the ladder is the most. Each step up the ladder restricts your freedom more. For example, an undertaking without conditions is at the bottom of the ladder. A house arrest is at the top of the ladder.
A person with no criminal record and no criminal charges is usually assumed to be at the bottom of the ladder. But, if the allegations against the person are serious the court may move them up the ladder to ease their concerns about releasing him or her.
The more offences the person has on their record and the more serious the offences are, the higher the person moves up the ladder.