COW	Interstate System, 1816-2004

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Overview

This data set contains the list of states in the international system as updated and distributed by the Correlates of War Project. These data sets identify states, their standard Correlates of War "country code" or state number (used throughout the Correlates of War project data sets), state abbreviations, and dates of membership as states and major powers in the internationaly system. Version 2004.1 extends the temporal domain of the collection to 2004. Users note: The order of variables in this file has changed from the 2002 version. The variables were incorrectly ordered in the 2002 version of this data set, and did not match the documentation (the first two variables were switched). In the 2004 version, variables are now in the correct order, and are identical between the "states" and "majors" data sets.

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Citation

We ask users of the data set to cite this data set as follows:

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Data Set

The files associated with the interstate system membership data set can be obtained either individually, or in one ZIP file that contains several files.

1	State Codebook 2004.1.pdf - describes the content and format of the state system membership datasets, and provides details of the operational criteria for state system membership.
2	State FAQ.pdf - Contains answers to some Frequently Asked Questions about the state system membership datasets.
3	states2004.csv - provides the entry and exit dates of states, country codes, and abbreviations.
4	majors2004.csv - provides the entry and exit dates for states to be designated as major powers.
5	system2004.csv - lists the composition of the state system year by year (providing a blank country-year dataset).

Click here to receive all files in a single zipped data set.

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File Specific Documentation

All data files associated with state system membership are in .csv (comma-delimited) format. In this format, values are separated by commas, with string values (e.g. state names) in quotations. The first line of each data file is a header record containing the variable names.

states.csv

This file contains a list of the COW states, numbers, abbreviations, and their qualifying periods of tenure in the state system. Users of the data set should note that states that leave and reenter the state system have more than one record in the data set. It includes the following fields, in order (Users note: The variables in the 2002 version of this data set did not match this list; the first two variables were switched. In the 2004 version, variables are now in this order, and are identical between the "states" and "majors" data sets):

State Abb	COW state abbreviation
State Num	COW state number
State Name	Primary COW state name
Start Year	Beginning year of state tenure
Start Month	Beginning month of state tenure
Start Day	Beginning day of state tenure
End Year	Ending year of state tenure
End Month	Ending month of state tenure
End Day	Ending day of state tenure
Version	Data file version number

majors.csv

This file contains a list of the COW major powers and their qualifying periods of tenure. Users of the data set should note that major powers that leave and reenter the major power system have more than one record in the data set. It includes the following fields:

State Abb	COW state abbreviation
State Num	COW state number
Start Year	Beginning year of major power tenure
Start Month	Beginning month of major power tenure
Start Day	Beginning day of major power tenure
End Year	Ending year of major power tenure
End Month	Ending month of major power tenure
End Day	Ending day of major power tenure
Version	Data file version number

system.csv

This file contains a year-by-year list of state system membership (and so, is a base country-year data set). A state is listed as being a member of the state system if it is recorded in states.csv as present in the system at any time during the relevant year. It contains 13,212 records with the following fields:

State Abb	COW state abbreviation
State Num	COW state number
Year	Observation year
Version	Data file version number

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Questions and Feedback

Questions about this data set may be emailed to correlates-of-war@psu.edu.