Property-crime rates are partly determined by the collective costs-benefits assessment of potential offenders. If more persons think the perceived gains outweigh the perceived costs, more crimes will be committed. The collective behavior of offenders influences the costs- benefits assessments of potential victims regarding their investment in security. If the perceived risks are thought to outweigh the perceived costs of extra security, the quantity and quality of protection measures will increase. If crime rates surpass a certain threshold, a countervailing force is mobilized that will retard the crime increase. The costs-benefits assessments of both parties can be expressed in curves that represent the relationship between the numbers of offenses and the average yields per offense. Offenders will commit more crimes if the yields are higher (the demand curve). Victims will minimize yields by increased security if the numbers of offenses increase (the supply curve). Crime rates will tend to stabilize at the point where the two curves intersect. In this perspective, the level of crime is determined by the interactions between the rational choices of offenders and victims at the macro level. The rational-interactionist model suggests that crime can be significantly decreased through actions by potential victims that increase their security and thus reduce opportunities for potential offenders. 6 figures and 49 references