The core function of organized crime is the selling of protection. Protection can be real, against third-party crime, or manufactured by the organized crime groups themselves. Mafias and gangs emerge in areas of weak state control, because of prohibition and geographic, ethnic, or social isolation. Although competition is considered good in economics, in the case of organized crime the predatory competition that is more likely to take place is harmful. The costs of organized crime include the resources expended on the activity, more ordinary productive and investment distortions, as well as other dynamic effects on occupational choice.