The objective of this research is to develop and empirically test a comparative organization analysis approach to the interpretation of structural outcomes in social movement organizations (HJs). Various patterns of MO characteristics are empirically described and subsequently interpreted within a conceptual scheme and typology of different organizations. Empirical data is employed to clarify and test the proposed conceptual framework using a systematic approach that is largely exploratory and descriptive. This research can be labelled as a comparative, organizational-level, survey analysis of MOs. Three pivotal variables are identified: relationship to environment, size, and centralization of decision making. A three-way cross-classification forms a typology of 12 "goal and task structures". The typology is analytically integrated within a conceptual framework that presumes system properties between external environmental variables and internal structural variables. Theoretical significance is.attributed to the role of ideology as an independent variable that influences systems of relationships in complex ways. The proposed typology is used to demonstrate theoretical and empirical linkages between external environmental variables and internal structural variables, and between ideological and organizational characteristics. In effect, an empirically based methodology is confirmed as an approach to substantive theoretical and practical issues.