Introducing the case studies

Mass atrocities – widespread and systematic violence against civilians – have proven easier to condemn than to stop. Yet these atrocities do eventually stop. Valuable lessons for halting future atrocities may be learned by studying past terminations.

This website provides case studies of endings (alpha listing of cases) assembled in this of “very massive atrocities,” defined as widespread and systematic killing of unarmed people (civilians or prisoners of war) within a single country resulting in at least 50,000 civilian fatalities in cases post-1945. This includes cases in which people were under the direct control of perpetrators, held in camps and prisons, and denied the means for sustaining life. We use a threshold of 5,000 civilian deaths in a given year, with onsets marked by the first year above this level, and endings marked as the final year at this threshold under a single perpetrator, when followed by two consecutive years below this level. If more than 5,000 civilians are killed by a separate perpetrator group within the subsequent two years, this is coded as a subsequent atrocity.

The universe of cases was established by drawing on diverse existing lists and datasets of atrocity and genocides plus additional research. Case studies for each atrocity episode in the dataset drew on expert qualitative analysis to outline the context for instability, describe the scale and pattern of atrocities, present the evidence base for fatality figures, and detail terminations. This process is inherently subjective and not all experts will agree on all conclusions. We consulted outside experts to help with these decisions and obtained in-depth reviews on difficult cases including the Africa cases, Iraq, Indonesia and Vietnam.

Unlike some datasets on mass atrocities, we include examples from anti-colonial conflicts, where the primary perpetrators are either state or non-state actors, and both war time and peacetime atrocities.

Throughout, we sought the most credible minimal number of fatalities.

We also offer a framework that organizes these endings into three types. First, atrocities end as planned when perpetrators achieve their aims, often by eliminating the threat they believed was posed by the targeted group. Second, atrocities can end when perpetrators were prevented from achieving their aims, notably through military defeat. The third ending type, labeled strategic shift, occurs when perpetrators retain power and capacity, and continue to pursue their initial goals, but through means that no longer rely upon mass killing of civilians. Such a shift may be a response to rising (military, political, or economic) costs of continuing the atrocities, failure to achieve the intended goals, or shifts in political power and preferences within the perpetrating organization.

Each case study is divided into five sections. These include: an introduction; atrocities, discussing the patterns of violence across the atrocities period; fatalities, a discussion of the research surrounding the numbers; endings, describing how the violence ended, in line with our criteria; and coding, explaining how and why we coded the ending. We further provide a list of works cited. (All variables in the dataset are detailed here).

We welcome your feedback, and ask that you include a real name and email address along with any comments or questions.