Reasonable doubt is a way to judge if someone is guilty or innocent of a crime. A jury has to decide if they think someone is guilty beyond a reasonable doubt. That means they have to be very sure that the person committed the crime. The jury reviews evidence to decide if the person is guilty. The evidence must be strong enough to convince the jury of something so that they do not have any doubt about it. If the jury is not sure if the person committed the crime, then the person should not be found guilty.