Change point analysis of historical battle deaths.

Summary: It has been claimed and disputed that World War II has been followed by a 'long peace': an unprecedented decline of war. We conduct a full change point analysis of well‐documented, publicly available battle deaths data sets, using new techniques that enable the robust detection of changes in the statistical properties of such heavy‐tailed data. We first test and calibrate these techniques. We then demonstrate the existence of changes, independent of data presentation, in the early to mid‐19th century, as the Congress of Vienna system moved towards its collapse, in the early to mid‐20th century, bracketing the World Wars, and in the late 20th century, as the world reconfigured around the end of the Cold War. Our analysis provides a methodology for future investigations and an empirical basis for political and historical discussions. [ABSTRACT FROM AUTHOR]