This is a data set on state-level estimates for the "ruggedness" of a state's terrain.
Format
A data frame with 192 observations on the following 6 variables.
ccodea Correlates of War state code
gwcodea Gleditsch-Ward state code
ruggedthe terrain ruggedness index
newlmtnestthe (natural log) percentage estimate of the state's terrain that is mountainous
Details
The data-raw directory on the project's Github contains more
information about how these data were created. It goes without saying that
these data move slowly so the data are really only applicable for making
state-to-state comparisons and not states-in-time comparisons. The terrain
ruggedness index is originally introduced by Riley et al. (1999) but is
amended by Nunn and Puga (2012). The mountain terrain data was originally
created by Fearon and Laitin (2003) but extended and amended by Gibler and
Miller (2014). The data are functionally time-agnostic, but all data sets
seem to benchmark around 1999-2000. You should still use it with some care in
your state- or dyad-year panel analyses. I'm not sure it matters that much,
but it matters a little at the margins, I suppose, if you suspect there are
major differences in interpretation of how much more "rugged" the Soviet
Union was than Russia, or Yugoslavia than Serbia.
References
Fearon, James D., and David Laitin, "Ethnicity, Insurgency, and Civil War" American Political Science Review 97: 75–90.
Gibler, Douglas M. and Steven V. Miller. 2014. "External Territorial Threat, State Capacity, and Civil War." Journal of Peace Research 51(5): 634-646.
Nunn, Nathan and Diego Puga. 2012. "Ruggedness: The Blessing of Bad Geography in Africa." Review of Economics and Statistics. 94(1): 20-36.
Riley, Shawn J., Stephen D. DeGloria, and Robert Elliot. 1999. "A Terrain Ruggedness Index That Quantifies Topographic Heterogeneity,” Intermountain Journal of Sciences 5: 23–27.