Changepoint analysis of historical battle deaths

TL;DR

This paper applies advanced changepoint detection methods to historical battle death data, identifying significant shifts around key historical periods, and offers a robust framework for analyzing heavy-tailed datasets in conflict studies.

Contribution

It introduces new techniques for robust changepoint detection in heavy-tailed data and applies them to historical battle death records, revealing significant change points around major wars.

Findings

Detected change points around 1910 and 1950 CE, bracketing the World Wars.

Identified additional change points around the 1830s and 1994 CE.

Provided a methodological framework for future conflict data analysis.

Abstract

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 changepoint analysis of well-documented, publicly-available battle deaths datasets, 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, at around 1910 and 1950 CE, bracketing the World Wars, and around the 1830s and 1994 CE. Our analysis provides a methodology for future investigations and an empirical basis for political and historical discussions.