Polity IV Score Distribution, 1800-2015

This chart displays the Distribution of Annual POLITY Scores in the annual times-series version of the Polity IV dataset. The black bars display the distribution for the entire data series, 1800-2015, and the color bars show the distribution for the "classic Westphalian state-system" (1800-1954) and the contemporary "global system of states" (1955-2015). The most dramatic differences between the two periods, in addition to the absence of local polities governing the colonial territories during the classic period, are 1) the concentration of personalist and corporatist (-7) autocracies in the contemporary period contrasting with the range of monarchies and reformist monarchies that dominated the classic period and 2) the (very recent) emergence of democratic polities in the contemporary period. The "local polities governing the colonial territories" during the classic period are subsumed by the imperial states in the Westphalian state-system. Earlier versions of the Polity data series included imcomplete information on these "local polities" by including data on "self-governing territories." This hybrid classification of "non-state" polities was almost invariably coded as "partially democratic" by definition and, thus, imparted a systematic bias to the data series. The Polity IV version includes only independent, state polities in the data series. In addition, the data series does not include "micro-states," that is, independent states with total populations less than 500,000 in the most recent year. The Polity IV data series covers 167 independent states in 2015 and is updated annually.