ABSTRACT Most people would agree that films can significantly impact individual attitudes and cultural narratives, but little research has sought to empirically measure these impacts. It is becoming increasingly important for documentary (and other issue-based) films to justify costs by providing data on the social “return on investment”, but care must be taken to ensure that both the questions asked and the methods used to answer them are valid and respectful. This paper introduces an emerging research agenda for the study of documentary film impacts, discussing both why such evaluation is important and key issues relevant to assessing impact. Author Keywords Film, Impact, Evaluation, Social Change INTRODUCTION Documentary film has grown significantly in the past decade, with high profile films such as Fahrenheit 9/11, Supersize Me, and An Inconvenient Truth garnering increased attention both at the box office and in the news media. In addition, the rising prominence of web-based media has provided new opportunities for documentary to create social impact. Films are now typically released with websites, Facebook pages, twitter feeds, and web videos to increase both reach and impact. This combination of technology and broader audience appeal has given rise to a current landscape in which documentary films are imbedded within coordinated multi-media campaigns. New media have not only opened up new avenues for communicating with audiences, they have also created new opportunities for data collection and analysis of film impacts. A recent report by McKinsey and Company highlighted this potential, introducing and discussing the implications of increasing consumer information being recorded on the Internet as well as through networked sensors in the physical world. As they found: "Big data—large pools of data that can be captured, communicated, aggregated, stored, and analyzed—is now part of every sector and function of the global economy" (Manyika et al. iv). This data can be mined to learn a great deal about both individual and cultural response to documentary films and the issues they represent. Although film has a rich history in humanities research, this new set of tools enables an empirical approach grounded in the social sciences. However, several researchers across disciplines have noted that limited investigation has been conducted in this area. Although there has always been an emphasis on social impact in film and many filmmakers and scholars have made legitimate (and possibly illegitimate) claims of impact, few have attempted to empirically justify these claims. Over fifteen years ago, noted film scholar Brian Winston commented that "the underlying assumption of most social documentaries—that they shall act as agents of reform and change—is almost never demonstrated" (236). A decade later, Political Scientist David Whiteman repeated this