This chart focuses on the distribution of POLITY scores in the contemporary "global system of states" period, 1955-2015. It includes information on the distribution of POLITY scores of the state at the point of onset for three types of "political instability events": negative regime changes (a collapse of central authority, -77, or a sudden shift toward greater autocratic authority defined by a continuous, negative change in POLITY score of five points or greater; continuity of such change is determined by changes occurring in succession with less than three years between changes); positive regime changes (a sudden shift toward more open and competitive authority defined by a continuous, positive change in POLITY score of five points or greater); and political violence onsets (systematic and sustained episodes of ethnic or revolutionary warfare involving state and non-state forces and resulting in 100 conflict-related deaths per annum and 1000 conflict-related deaths over the course of the episode). Information used to identify both "positive" and "negative" regime changes is derived from the Polity IV data series and information used to identify "political violence onsets" is taken from the Political Instability Task Force (PITF) Problem Set. Both data sources are collected and compiled by the Center for Systemic Peace; refer to the INSCR data page for more information and access to the data resources used here. "Other" POLITY scores include 99 (year of independence), -88 (regime transition), -77 (interregnum; collapse of central authority), and -66 (foreign interruption).