The crucial distinction is the level of service, treatment and interventions; the amount of time that is allowed out of the cell during the day, which will be doubled in an SIU compared with administrative segregation; and again, the whole orientation of the system.
Under administrative segregation, the heavy emphasis has been on the control and safety and security imperatives, without continuing treatment. In a structured intervention unit, the security features are maintained, but the objective is to ensure that the treatment, interventions and programming will continue and perhaps even be enhanced, particularly with respect to mental health, to make sure that the individual gets less dangerous and not more dangerous.