Supermaximum-security prisons—or “supermaxes”—symbolize the “get tough” criminal justice policies that have developed over the past three decades in the United States and in other countries. Proponents believe that they effectively address critical prison system problems; opponents believe that they do not and that they create substantial harm. This essay examines the available evidence about supermaxes.
A range of considerations are relevant to determining whether supermaxes constitute effective policy. These include (a) definitional problems in discussing supermax incarceration; (b) five critical dimensions along which evidence for policies is desirable and along which supermaxes fall short, including demonstration of policy need, credible policy theory, high-quality implementation, impact, and benefits that exceed costs and do so more than other policies; (c) the challenge of assessing causal claims related to supermaxes; (d) legal and ethical issues; (e) policy and political challenges confronting states; (f) policy options other than supermaxes; and (g) research gaps that remain to be addressed. The essay argues that causal uncertainty about supermax incarceration makes it difficult at present to claim credibly that it achieves intended goals. Policy implications and recommendations are discussed.