Polity IV Project:
Political Regime Characteristics
and Transitions, 1800-2012


Monty G. Marshall, Director

Monty G. Marshall, Principal Investigator

Societal-Systems Research Inc.
Ted Robert Gurr, Founder
University of Maryland (Emeritus)


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The Polity IV Project continues the Polity research tradition of coding the authority characteristics of states in the world system for purposes of comparative, quantitative analysis. The original Polity conceptual scheme was formulated, and the original Polity I data collected, under the direction of Ted Robert Gurr; the Polity scheme was informed by foundational, collaborative work with Harry Eckstein, Patterns of Authority: A Structural Basis for Political Inquiry (New York: John Wiley & Sons, 1975). The Polity project has proven its value to researchers over the years, becoming the most widely used data resource for studying regime change and the effects of regime authority. The Polity IV Project carries data collection and analysis through 2012 and is under the direction of Dr. Monty G. Marshall and supported by the Political Instability Task Force, Societal-Systems Research Inc, and Center for Systemic Peace.

Brief Description: The Polity conceptual scheme is unique in that it examines concomitant qualities of democratic and autocratic authority in governing institutions, rather than discreet and mutually exclusive forms of governance. This perspective envisions a spectrum of governing authority that spans from fully institutionalized autocracies through mixed, or incoherent, authority regimes (termed "anocracies") to fully institutionalized democracies. The "Polity Score" captures this regime authority spectrum on a 21-point scale ranging from -10 (hereditary monarchy) to +10 (consolidated democracy). The Polity scores can also be converted to regime categories: we recommend a three-part categorization of "autocracies" (-10 to -6), "anocracies" (-5 to +5 and the three special values: -66, -77, and -88), and "democracies" (+6 to +10); see "Global Trends in Governance, 1800-2012" above. The Polity scheme consists of six component measures that record key qualities of executive recruitment, constraints on executive authority, and political competition. It also records changes in the institutionalized qualities of governing authority. The Polity data include information only on the institutions of the central government and on political groups acting, or reacting, within the scope of that authority. It does not include consideration of groups and territories that are actively removed from that authority (i.e., separatists or "fragments"; these are considered separate, though not independent, polities) or segments of the population that are not yet effectively politicized in relation to central state politics.

The Polity project has evolved through three earlier research phases, all under the direction of Ted Gurr. The Polity III phase updated core Polity data through 1992 and was later updated through 1998 and released as the Polity98 version. Through its evolution, the format of the Polity data has been transformed from its original focus on "persistence and change" in the "polity" as the unit of analysis (i.e., polity-case format) to its present country-year case format, which is the preferred format for inclusion in time-series analyses. The original Polity I format was revisited by a research team under the direction of Nils Petter Gleditsch and information concerning the dates of polity changes was updated in 1994 and made available in the original polity-case format as Polity IIId. In the late 1990s, Polity became a core data project in the U.S. Government's State Failure Task Force global analysis project (since, renamed the Political Instability Task Force; PITF). The special focus on "state failure" problem events within a general context of societal and systemic development processes requires information pertinent to both Polity foci, that is, state continuity and change (country-year format) and regime persistence and change (polity-case format), be combined in a single data resource base. The fourth phase of the project, Polity IV, combines information from those two formats in a single data resource. Annual Polity IV records code the regime characteristics in effect on December 31 of the record year and provide the dates and magnitide of Polity changes that occurred during the record year.
Click on Image for Detailed Explanation of Polity Distribution
Click on Image for Detailed Explanation of this Chart
The Polity IV dataset covers all major, independent states in the global system (i.e., states with total population of 500,000 or more in the most recent year; currently 167 countries) over the period 1800-2012. With the support of the PITF, the Polity IV Project has been transformed into a living, data collection effort, meaning that it constantly monitors regime changes in all major countries and provides annual assessments of regime authority characteristics and regime changes and data updates. It is also the most closely scrutinized data series on political issues as analysts and experts in academia, policy, and the intelligence community regularly examine and often challenge Polity codings. Monitoring real-time events requires Polity analysts to make tentative assessments of the trajectories of unfolding political dynamics and their effect on the essential qualities of governing institutions, or patterns of authority. Recent annual Polity records are routinely re-examined during each annual update and may be revised in light of further information regarding institutional practice. In addition, historical cases are often re-examined, often as a result of questions raised by users and country experts, and may be refined in conformance with new information or the correction of errors in the records. Along with the annually updated version of the Polity IV data series, we provide a separate record of substantive changes made to the data records during the annual update procedure (simple corrections are not reported). We also provide a separate version of the dataset in "polity-case" format: Polity IVd. The standard method for documentation of data collection in the social sciences, that is, coding sheets, has been replaced by a more detailed description of Polity characteristics and changes for each individual country in the data series: the annual Polity IV Country Report series. We have also compiled a list of non-constitutional changes in executive leadership (e.g., coups d'etat, revolutions, or forced resignations) that may not be captured in changed Polity scores or may result in only minor changes of Polity scores. The Polity IV data resources and Country Report series are now hosted on the Center for Systemic Peace Web site. Click on any of the four graphs displayed in this section for a more detailed explanation of the nuanced characteristics Polity data series and its relationship to conflict management and the onset of political instability. Click on the links below to access to the most recent version of the Polity data series and country reports.



Global Report 2011
is now available
Click image above to view
The 2012 update of the Polity IV data series is now posted on the INSCR Data Page
The Country Report series is currently updated through mid-2011

The Polity IV Project is part of Societal-Systems Research Inc and the
Center for Systemic Peace

Center for Systemic Peace Home Page


Global Report 2011 and State Fragility Matrix 2012

Polity IV Data Series version 2012

Polity IV Country Report 2010 Series
Click on Image for Detailed Explanation of this Chart
Click on Image for Detailed Explanation of this Chart

Polity IV Individual Country Regime Trends, 1946-2010

Annual Polity scores have been plotted for each of the 167 countries currently covered by the Polity IV data series for the period 1946-2012 (also included with the Polity IV Country Reports). The new version 2012 graphs display periods of "factionalism" and important Polity change events, including autocratic backsliding, executive auto-coup or autogolpe, revolution, collapse of central authority (state failure), and successful military coups. The old version graphs plotted major political violence events in relation to the annual Polity scores, including interstate and independence war, ethnic and revolutionary war, and genocide and politicide. Click on the country of interest in the "Regimes by Type 2012" map (or table) below to view that country's contemporary trends (click here for a explanatory guide to the trends graphs).

Canada United States United States Mexico Guatemala El Salvador Honduras Cuba Nicaragua Costa Rica Panama Haiti Dominican Republic Jamaica Colombia Ecuador Peru Bolivia Venezuela Trinidad & Tobago Guyana Paraguay Uruguay Argentina Chile Brazil Ireland United Kingdom Norway Sweden Finland Estonia Latvia Lithuania Denmark Netherlands Belgium Portugal Spain France Switzerland New Zealand Australia East Timor Indonesia Singapore Malaysia Philippines Taiwan Japan South Korea Germany Poland Czech Republic Slovak Republic Solomon Islands Papua New Guinea North Korea Belarus Moldova Ukraine Austria Slovenia Croatia Hungary Bosnia Montenegro Albania Serbia Macedonia Romania Bulgaria Greece Italy Turkey Cyprus Lebanon Israel Syria Jordan Georgia Armenia Azerbaijan Kazakhstan Kyrgyzstan Tajikistan Uzbekistan Turkmenistan Mongolia Kuwait Bahrain Qatar Iraq Iran Fiji Afghanistan Pakistan Nepal Bangladesh Bhutan Sri Lanka India India Myanmar Thailand Laos Cambodia Vietnam China Russia United Arab Emirates Oman Saudi Arabia Yemen Mauritius Comoros Madagascar Djibouti Eritrea Lesotho Swaziland South Africa Botswana Namibia Zimbabwe Malawi Mozambique Angola Zambia Burundi Rwanda Tanzania Uganda Kenya Somalia Ethiopia Sudan DRCongo Congo Gabon Equatorial Guinea Cameroon Central African Republic Chad Egypt Libya Tunisia Gambia Guinea Bissau Senegal Guinea Sierra Leone Liberia Mauritania Morocco Ivory Coast Ghana Togo Benin Burkina Faso Mali Nigeria Niger Algeria Suriname South Sudan Luxembourg

The "State Fragility Index" was developed by Monty G. Marshall at the Center for Systemic Peace and has been an annual feature in the Global Report series, click here to view the 2007, 2008, 2009, and 2011 Global Reports in the CSP Virtual Library. The 2011 Global Report was published in December 2011 by the Center for Systemic Peace; the State Fragility Index and Matrix is included in Global Report 2011, which can be viewed in PDF by clicking here. The most recent State Fragility Matrix (year 2012 data) is now available in PDF format by clicking here. The full, annual State Fragility data series (1995-2012) is available on the INSCR Data Page.

Polity IV Individual Country Regime Trends, 1946-2012
Click here to view Legend Key for Trends Graphs

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* The research described in the Polity IV Project was sponsored by the Political Instability Task Force (PITF).
The PITF is funded by the Central Intelligence Agency. The views expressed herein are the author's/authors' alone and do not
represent the views of the US Government.

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Last updated on June 10, 2013
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