社会運動
Social movement impact theory has been studied far less than most other subcategories of social movement theory, mostly due to methodological issues. It is relatively new, and was only introduced in 1975 with William Gamson's book "The Strategy of Social Protest", followed by Piven and Cloward's book "Poor People's Movements". In his groundbreaking study, Gamson studied 53 social movement organizations from between 1800 and 1945, and collected data regarding their success. Among Gamson's most important findings were that organizations which attempt to displace a specific person in power are almost never successful; that movement violence is a symptom of success (not a cause of it); that bureaucratic organizations are more likely to be successful, but also more likely to be co-opted by elites; and that organizations that are allowed to emerge in times of political calm are more successful during times of turbulence. These findings catalyzed some of the major debates in impact theory.