the practice is used when a prisoner is considered dangerous to themselves or to others, is suspected of organizing or being engaged in illegal activities outside of the prison, or, as in the case of a prisoner such as a pedophile or witness, is at a high risk of being harmed by another inmate or inmates. the latter example is a form of protective custody. solitary confinement is also the norm in supermax prisons where prisoners who are deemed dangerous or of high risk are held. it may be hard to determine the number of people currently being held in solitary confinement because some prisons have a hard time defining it. however, it is estimated that 80,000 to 100,000 people are currently in solitary confinement within the usa.