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National Material Capabilities (v4.0)

Power is considered by many to be a central concept in explaining conflict, and six indicators - military expenditure, military personnel, energy consumption, iron and steel production, urban population, and total population - are included in this data set. It serves as the basis for the most widely used indicator of national capability, CINC (Composite Indicator of National Capability) and covers the period 1816-2007.

National Material Capabilities (v4.0)


The National Material Capabilities data set contains annual values for total population, urban population, iron and steel production, energy consumption, military personnel, and military expenditure of all state members, currently from 1816-2007. The widely-used Composite Index of National Capability (CINC) index is based on these six variables and included in the data set.

Citation and History  

In any  paper or publication that use this data set, user are asked to give the version number and cite an article of record for the data set as follows:

Singer, J. David, Stuart Bremer, and John Stuckey. (1972). "Capability Distribution, Uncertainty, and Major Power War, 1820-1965." in Bruce Russett (ed) Peace, War, and Numbers, Beverly Hills: Sage, 19-48.

The above article, the first NMC data set assembled in the 1960s, described and analyzed original data on major powers only. Following this, the data set was expanded to cover the entire interstate system as discussed in:

Singer, J. David. 1987. "Reconstructing the Correlates of War Dataset on Material Capabilities of States, 1816-1985" International Interactions, 14: 115-32.

Data Set 

Version 4.0 of the data set covers the period 1816-2007 contains the set of raw data values for the six basic indicators within the data set along with the computed Composite Index of National Capability (CINC) score, along with a file describing its format, and documentation for the construction of these indicators. The data consist of two parts:

1. NMC Codebook v4The codebook for version 4.0 of the data identifying the variables, variable order, and format of the data set.

2. NMC v4: The data in comma-separated variable format. 

Subcomponent Data 

The main data set above contains data on six individual components. The COW project maintains information on data sources, interpolation methods, the quality of individual data points, and noted anomalous values in the data. These subcomponent data points, in both .csv and .dta formats, are :

1. NMC Supplement v4 (.csv): ZIP file of the underlying .csv data base for CINC components.

2. NMC Supplement v4 (.dta): ZIP file of the underlying data base for CINC components in .dta format.

Important Notes on the Use of Raw Capability Data 

Values for total population, urban population, iron and steel production, energy consumption, military personnel, and military expenditure for each state-year were originally collected to construct the composite index of national capabilities. These components are offered here but the user of these data should be warned that the quality and quantity of the data vary greatly from state to state and from year to year. In particular, each of the six indicators has its own idiosyncracies that limit cross-time comparability.  Hence, those who use the raw data in time-series analyses should do so with caution.  Users of the data are strongly urged to read the NMC codebook. 

Derived Indicator 

Annual values for the computed Composite Index of National Capability (CINC) score are included with this data set. This measure is generally computed by summing all observations on each of the 6 capability components for a given year, converting each state's absolute component to a share of the international system, and then averaging across the 6 components. 

NMC codebook

This file was downloaded 5941 times.
The codebook for version 4.0 of the data identifying the variables, variable order, and format of the data set.

PDF document icon NMC_Codebook_v4_0.pdf — PDF document, 707 kB (724093 bytes)

NMC v4 data

This file was downloaded 5729 times.
The data in .csv format.

text/comma-separated-values icon NMC_v4_0.csv — text/comma-separated-values, 732 kB (750379 bytes)

NMC Supplement v4 (.csv)

This file was downloaded 2047 times.
ZIP file of the underlying .csv data base for CINC components.

Zip archive icon — Zip archive, 622 kB (637013 bytes)

NMC Supplement v4 (.dta)

This file was downloaded 1391 times.
ZIP file of the underlying data base for CINC components in .dta format.

Zip archive icon — Zip archive, 1197 kB (1226139 bytes)

Changes in NMC

Changes in version 4.0

Version 4.0 expands the data to 2007. In addition, the subcomponent data points are now maintained in .csv format and in a single file for greater convenience.


Changes in version 3.02

Version 3.02 corrects component values for Singapore's population and energy statistics from 1965-2001. First, some prior energy values were underestimated due to the availability of limited data, which have now been updated (and new backwards extrapolation applied). Second, due to using midyear and end-of-year sources, Singapore's urban population sometimes appearead greater than its total population (it is 100% urban). These values were corrected. In addition, data were added for Tuvalu, Kiribati, Tonga, and Nauru (data was missing in v3.01) from 1999-2001. Overall CINC scores were then recomputed for all states in the database; most changed in the 4th decimal place. The main documentation was also slightly updated at this time (simply to list the capability units used in the main data set).


Change in version 3.01

Version 3.01 changes one (and only one) component value of the 72,000 country-year-values, namely Russia's value for military personnel in 2000. This entry had a typo (15200 as opposed to the correct 1004). This one change has an important effect on Russia's CINC score in 2000 (lowering it from .11 to .05).


Changes in version 3.0

Version 3.0 makes a number of changes to the component data within the data set, although the final correlation of CINC scores to CINC scores computed using version 2.1 is extremely high (r=0.99). Construction of version 3.0 of the capabilities data set has included both an update of each time series to 2001 and a thorough revisiting of some of the individual component series. In particular:


-The Military Personnel Data Set was both updated and modified. It was modified from previous versions by using U.S Arms Control and Disarmament Agency (ACDA) data for all data points from 1961 forward when possible. This solitary data source makes the data more comparable both cross-nationally and longitudinally.


-The Iron and Steel Data Set was both updated and modified. Project researchers went back through the data set and re-confirmed the data points, re-documenting the sources for all data points in the series.


-The Primary Energy Consumption Data Set was completely re-constructed for version 3.0. All data points were re-calculated from raw data sources, and compiled into a total energy consumption data value for each state in a given year.

-The Total Population Data Set was first updated using United Nations data. Then researchers went back through the data set, re-documenting the data points; some data series were replaced, and some interpolations were re-calculated.


As part of extending and modifying the data set, project researchers have also fully documented as many data points as possible within a set of larger computer databases for each component, and created new "quality" and "anomaly" codes within the individual component sets. These codes mark data points for which we have greater or lower confidence in the accuracy of the point, and mark unexplained jumps or declines in the data values that may indicate measurement problems. We anticipate releasing these component data bases in the future.

Earlier Versions

Version 1.0 of the NMC data, which covers the period 1816-1985,  may be obtained from the Inter-university Consortium for Political and Social Research (ICPSR) as study number 9903 (National Material Capabilities Data, 1816-1985 ). The abstract of the data set may be viewed by clicking here.


Questions and Feedback

The national material capabilities data are hosted by J. Michael Greig, University of North Texas, and Andrew Enterline, University of North Texas, under the COW Data Set Hosting Program. In case of questions or concerns concerning the data or coding rules, they may be contacted by email at and