COW National Material Capabilities (v4.0)


The National Material Capabilites 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 papers or publications that utilize this data set, users are asked to give the version number and cite an article of record for the data set, as follows:

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

Data Availability and Download

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.

NMC_Codebook_v4_0.pdf The codebook for version 4.0 of the data identifying the variables, variable order, and format of the data set.
NMC_v4_0.csv The data in comma-separated variable, ASCII format

Click here to receive both files of NMC v4.0 in a single zipped data set.

Important Notes on 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 National Material Capabilities Documentation.

Derived Indicator: CINC

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. 

Subcomponent Datasets

The main data set above contains data on six individual components. The COW 2 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 available here. Zipped archive of the underlying .csv data base for CINC components. Zipped archive of the underlying data base for CINC components in Stata 10 format.

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:

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 Capabilites Data, 1816-1985 ). The abstract of the data set may be viewed by clicking here.

Version 2.1 of the data may still be obtained here.


Questions and Feedback

The national material capabilities data are hosted by 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