add_contiguity: Add Correlates of War direct contiguity information to a data...

View source: R/add_contiguity.R

add_contiguityR Documentation

Add Correlates of War direct contiguity information to a data frame


add_contiguity() allows you to add Correlates of War contiguity data to a dyad-year, leader-year, or leader-dyad-year, or state-year data frame.





a data frame with appropriate peacesciencer attributes


The contiguity codes in the dyad-year data range from 0 to 5. 1 = direct land contiguity. 2 = separated by 12 miles of water or fewer (a la Stannis Baratheon). 3 = separated by 24 miles of water or fewer (but more than 12 miles). 4 = separated by 150 miles of water or fewer (but more than 24 miles). 5 = separated by 400 miles of water or fewer (but more than 150 miles).

Importantly, 0 are the dyads that are not contiguous at all in the CoW contiguity data. This is a conscious decision on my part as I do not think of the CoW's contiguity data as exactly ordinal. Cross-reference CoW's contiguity data with the minimum distance data in this exact package to see how some dyads that CoW codes as not contiguous are in fact very close to each other, sometimes even land-contiguous. For example, Zimbabwe and Namibia are separated by only about a few hundred feet of water at that peculiar intersection of the Zambezi River where the borders of Zambia, Botswana, Namibia, and Zimbabwe meet. There is no contiguity record for this in the CoW data. There are other cases where contiguity records are situationally missing (e.g. India-Bangladesh, and Bangladesh-Myanmar in 1971) or other cases where states are much closer than CoW's contiguity data imply (e.g. Pakistan and the Soviet Union were separated by under 30 kilometers of Afghani territory). The researcher is free to recode these 0s to be, say, 6s, but this is why peacesciencer does not do this.

For additional clarity, the "master records" produce duplicates for cases when the contiguity relationship changed in a given year. This function returns the minimum contiguity relationship observed in that given year. There should be no duplicates in the returned output.

Be mindful that the data are fundamentally state-year and that extensions to leader-level data should be understood as approximations for leaders in a given state-year.


add_contiguity() takes a data frame and adds information about the contiguity relationship based on the "master records" for the Correlates of War direct contiguity data (v. 3.2). If the data are dyad-year (or leader dyad-year), the function returns the lowest contiguity type observed in the dyad-year (if contiguity is observed at all). If the data are state-year (or leader-year), the data return the total number of land and sea borders calculated from these master records.


Steven V. Miller


Stinnett, Douglas M., Jaroslav Tir, Philip Schafer, Paul F. Diehl, and Charles Gochman (2002). "The Correlates of War Project Direct Contiguity Data, Version 3." Conflict Management and Peace Science 19 (2):58-66.


# just call `library(tidyverse)` at the top of the your script

cow_ddy %>% add_contiguity()

create_stateyears() %>% add_contiguity()

peacesciencer documentation built on March 31, 2023, 8:37 p.m.