Opportunity structure is the framework of socially structured means and rules available for a social group to achieve its aims and interests, which are culturally defined and oriented toward social success. Build on Robert K. Merton's theory of anomie, the concept was developed by Richard A. Cloward and Lloyd E. Ohlin in their works on delinquent subcultures. From the last decades of the twentieth century, the concept was extensively developed in the analysis of collective action under the name of political opportunity structure by authors such as Charles Tilly, Sidney Tarrow, and Doug McAdam.