The analysis combines economic theory with data from a previous study of the types, prices, and availability of contraband in a maximum security prison, the State prison in Jackson, Mich. It found that consumption patterns for contraband do not respond proportionately to changes in price. As a result, changing the flow of contraband by checking visitors or prisoners more thoroughly, redesigning the prison environment, changing staff routines, or changing inmate turnover can contribute to instability in several ways. Shortages of contraband lead to increased thefts and extortion by inmates trying to get more revenue to pay the higher prices. Changes in prices and availability of contraband can also lead to instability in the inmate leadership structure. These changes all increase the potential for violent disputes about market 'territory' and other issues. However, prison managers could challenge the contraband market system by offering more opportunities in the legitimate sector of the prison economy, controlling the items that pose most risk to the prison community, and by being aware of what items could substitute for items for which demand is most fixed. Controlling contraband might also be easier in smaller institutions. Tables, 1 footnote, and 17 references. (Author abstract modified)