What were some forms of punishment during the Middle Ages and how effective were they?
During the Medieval Period, Europe was very loosely organized in terms of government, including law codes. Law and justice were mostly carried out by those who worked for the local King or Lord, and the most severe crimes were those which affected this ruler. For example, a peasant who stole from their neighbor was likely to receive a far less severe punishment than one who stole from the King.
As with any sort of punishment for a crime, the intent of punishment in the Medieval Period was to deter people from ever committing that crime again. There were not rehabilitative forms of penance, as there are in some countries today. People who committed crimes might be subjected to anything from a fine to dismemberment. Those who were repeat offenders might begin with a rather tame punishment (such as banishment) and progress to something more severe with further crimes (like being burned at the stake.)
Punishments were often designed to "fit" or reflect the crime a person had committed. Someone with repeated instances of theft, or one very hefty instance of theft, might have their hands cut off. Some crimes were punished by torture or the use of various devices, especially when one was believed to have committed a crime yet would not confess. People were subjected to such bodily pains as burning, being eaten alive by rats, or being locked up in public stocks to be beaten by others.
On the whole, Medieval forms of punishment were so psychologically and physically damaging that if a person did not die as a result of their punishment, they most certainly did not commit that crime again. And if they did, there was always execution.