This comparative study investigates the claim that open government data (OGD) should have a noticeable impact on marginalized groups’ inclusion in policy making. OGD researchers and practitioners conceptualize that society’s marginalized use OGD to achieve inclusion by overcoming information asymmetries and holding government accountable with data-supported claims. While this notion of OGD as a tool for social change through political advocacy is plausible, the research reports little evidence of social impact. In a comparative study of social projects in Hong Kong, the Dominican Republic, and Chile, I conducted a qualitative investigation into why OGD’s social impact is so elusive. In each case I traced OGD through political, technical, and social processes to determine if and how OGD empowers marginalized groups. Over ten months, I conducted one-hundred interviews with social movement leaders and participants, public officials, and data intermediaries. After transcribing and translating interview texts, I used thematic open coding to analyze interview data. As a result, I identified what social, political, and technical preconditions increased the propensity of social movement organizations and activists to make use of OGD to achieve a social impact. According to my findings, the claim that marginalized groups make use of OGD to achieve increased inclusion in policy making is inaccurate and inappropriate. This research brings clarity to what claims can be made for a social impact of OGD. Five main takeaways emerged: marginalized groups do not make use of OGD to achieve social change through political advocacy; academics and practitioners should modify their conceptualization and measurement of social impact to reflect a generative interpretation of empowerment; democratic systems are more conducive to civic reuse of OGD in articulating claims on government with economic and political elites; and the sociopolitical context, specifically the neoliberal reform experience, is an important determinant of the reuse of OGD to achieve social change. I also make three recommendations based on these findings to the OGD research and practitioner community.