Kristian Skrede Gleditsch

This site provides links to the POLITY IV project, the modified P4 and P4D data, and older versions of the Polity data. Click here for the official page for the Polity IV project.

The POLITY Project has evolved since the 1970s and has become a widely used source of cross-national, longitudinal data on the authority characteristics of modern polities.It is most widely used for its assessements of the degree of democracy and autocracy in the political structures of nation states. The current data releases in the public domain cover the time period 1800-2002.

Summaries of the project can be found in:

  • Gleditsch, Kristian S. and Michael D. Ward. 1997. "Double Take: A Re-examination of Democracy and Autocracy in Modern Polities." Journal of Conflict Resolution 41 (June):361-382.
  • Gurr, Ted Robert, Keith Jaggers, and Will H. Moore. 1989. "Polity II Codebook." Unpublished manuscript, University of Colorado (see below for an electronic copy).
  • Gurr, Ted Robert, Keith Jaggers, and Will H. Moore. 1990. "The Transformation of the Western State: The Growth of Democracy, Autocracy, and State Power since 1800. Studies in Comparative International Development 25 (Spring):73-108.
  • Gurr, Ted Robert. 1974. "Persistence and Change in Political Systems, 1800-1971." American Political Science Review 74 (December): 1482-1504.
  • Jaggers, Keith and Ted Robert Gurr. 1995. "Transitions to Democracy: Tracking Democracy's Third Wave with the Polity III Data." Journal of Peace Research 32 (November):469-82.

Polity 4 and Polity 4D data

The most recent version of the Polity data is available from this webpage administered by Monty G. Marshall. Please direct all question about these data to Monty G. Marshall at

Modified Polity 4 and Polity 4D data

The Polity data are not based on an explicit list of the universe or population of units. For example, the Polity data lack information about the characteristics of various independent states for certain time periods (for example, Switzerland 1816-1848) and also include observations for Polities that are not independent states (e.g., Norway before independence in 1905)

To make it easier to use these data in analyses where the universe is the population of independent states, I have created alternate versions of the P4 and P4D data that conform with the population in the Gleditsch and Ward list of independent states.

These data modify various unit labels and dates in the Polity data, and also contain estimates of the polity scores of states not in the original Polity data. Note that although these data are based on the Polity data they differ substantially in the population or units of observations. They also contain extrapolations and estimates not included in the original Polity data. They are provided to facilitate use of the data for research purposes different from those envisoned by the Polity project. However, these modified versions of the data are not endorsed by the Polity project in any way.

  • Click here for start end data, with one line per polity (ksgp4duse.asc)
  • Click here for annualized modifed data (ksgp4use.asc)
  • Click here for readme file for the modified data

If you wish to refer to these data specifically rather than the original Polity 4 data, please use the following citation:

Gleditsch, Kristian Skrede. 2018. Modified Polity P4 and P4D Data, Version 4.3., URL:

All inquiries about the POLITY project should be directed to:
Monty Marshall
Center for Systemic Peace
426 Center Street North
Vienna, VA 22180, USA


Keith Jaggers
4655 Chestnut Ln.
Boulder, CO 80301, USA

Inquiries about this website or the modified data:
Kristian Skrede Gleditsch (ksg at essex ac uk, insert @ and dots)
Department of Government
University of Essex
Wivenhoe Park
Colchester, CO4 3SQ, UK


The most recent version of the Polity data is available from the Center for International Development and Conflict Management at the University of Maryland. Please direct all question about these data to Monty G. Marshall at


This version of the polity data integrates the most recent annual version of the data - POLITY98 - with the dates in the POLITY3D data set whenever available (changes set to 31/12 and 01/01 otherwise).

This version was created from the two original datasets by Kristian Skrede Gleditsch to help facilitate integrating the two versions of the POLITY data in the public domain. Although POLITY98D strictly speaking contains no new data, these data provide more precision than the data aggregated to the annual level. Comments and suggestions are highly encouraged. The 15 November 2000 data entail some modficiations to start and end dates that appeared to be incorrect.

An ascii copy of the data can be found here


A slightly modfied alternate ascii copy of the POLITY 98 data can be found here

All inquiries about the data should be directed to Keith Jaggers (, or Ted R. Gurr (


Download a copy of the POLITY 3 data (ascii version) You may also download an ascii version of the codebook describing the POLITY 3 data. These data are described in:

  • Jaggers, Keith and Ted Robert Gurr. 1996. POLITY III: Regime Change and Political Authority, 1800-1994. [computer file] (Study #6695). 2nd ICPSR version. Boulder, CO: Keith Jaggers/College Park, MD: Ted Robert Gurr [producers], 1995. Ann Arbor, MI: Inter-University Consortium for Political and Social Research [distributor], 1996.

The associated ascii readme file outlines some principal changes and corrections made to the first release of the Polity database.


This POLITY3U (i.e., update) data set is a preliminary update and revision of the POLITY III database covering the period 1800-1996. This file contains only the summary indicators of democracy and autocracy, and is posted "as received" from Keith Jaggers.

Download a copy of the POLITY 3U data (ascii version). See also the associated readme file.


The POLITY3D dataset was collected using the above POLITY3 data as a baseline, but added to that specific dating information about each polity change to allow for better temporal calibration with other datasets. The POLITY 3D dataset is introduced in:

  • McLaughlin, Sara; Scott Gates, Håvard Hegre, Ranveig Gissinger, and Nils Petter Gleditsch. 1998. "Polity 3D: The timing of polity changes" Journal of Conflict Resolution 42:231-242.

The first version of the Polity 3 was released in December 1997. A slightly revised version was released 31 March, 1998. Click here for a memo outlining the principal changes and corrections made to the first release on December 1997. A new version of the ascii file containing the data with a slightly modified format for the dates was posted on 15 April, 1998. No changes were made to the actual data from the 03.31.98 release. On 7 June 2000 a minor error was corrected in the start or end dates of two polities (no. 1810 and no. 1820) for Panama in 1978. The 15 November 2000 data entail some modficiations to start and end dates that appeared to be incorrect.

The POLITY 3d data set consist of two data files:

  • POLITY3d - containing the actual data (ascii)
  • Source3D - indicating sources used in coding (dBase or ascii formats)

Codebook: The data are documented in the following sources:

Coding sheets: The actual coding sheets for the POLITY 3D data have been made available by the PRIO team, and can be downloaded here

Contact information: Haavard Hegre (hhegre 'at' prio 'dot' no), International Peace Research Institute Oslo, Fuglehauggata 11, N-0260 Oslo, Norway.


The POLITY 2 data are still available from the ICPSR (study number #9263) but are no longer widely used. However, the codebook for the POLITY 2 data is still quite useful in understanding and decoding the more recent versions of the data. Accordingly, we have scanned this document (with the permission of the authors) and post a streamlined version of that early document here for archival purposes. Here are the links: Acrobat, Microsoft Word, Postscript, or ascii formats.

Likewise, the POLITY 3D coding sheet may help illustrate the decisions that have been applied in assigning scores to particular countries.


These data are provided as is, with the permission of the authors and stewards of the databases. They are intended for noncommercial uses in the scholarly community.

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