One theme is that the commercial imperative of making a profit means that there is an almost irresistible structural incentive for private operators of prisons to cut costs and reduce standards. A second theme is that there is insufficient evidence to support the argument that the private operators can deliver equivalent or superior services more cheaply than the public sector agencies. A third theme is that accountability mechanisms are inadequate and seem largely to depend on the operators voluntarily being "benevolent and humanistic." Another theme is that the private operators will become a penal lobby for harsher penalties and more frequent use of imprisonment, so as to maintain and increase their market share. Papers also argue that there are no robust methodologies currently available for reliably and validly evaluating the comparative performance of the public and private sectors in prison management. Papers further maintain that there is excessive secrecy on the part of both the private operators and governments regarding the operation of private prisons; that privatization may be losing its appeal as private operators focus more on selling their services than on providing quality performance; and that fundamental issues about prison labor have re-emerged with privatization in a much sharper form. 8 references