About 20 states, including Arizona, Illinois and Maryland, have shifted all or portions of their prison healthcare operations to private providers in an attempt to cut costs, a trend that is raising concerns among unions and prisoners' rights groups. Officials in the states say the companies—which provide medical, dental, mental and pharmaceutical services—are less expensive than employing state workers, in part because using them saves on benefits and pension costs. Human rights groups, however, say that private operators are not always providing care that is as good or better than what the state could do.