create_dyadyears() allows you to dyad-year data from either the Correlates of War (CoW) state system membership data or the Gleditsch-Ward (gw) system membership data. The function leans on internal data provided in the package.

create_dyadyears(system = "cow", mry = TRUE, directed = TRUE)

Arguments

system

a character specifying whether the user wants Correlates of War state-years ("cow") or Gleditsch-Ward ("gw") state-years. Correlates of War is the default.

mry

optional, defaults to TRUE. If TRUE, the function extends the script beyond the most recent system membership updates to include observation to the most recently concluded calendar year. For example, the Gleditsch-Ward data extend to the end of 2017. When mry == TRUE, the function returns more recent years (e.g. 2018, 2019) under the assumption that states alive at the end of 2017 are still alive today. Use with some care.

directed

optional, defaults to TRUE. If TRUE, the function returns so-called "directed" dyad-year data. In directed dyad-year data, France-Germany (220-255) and Germany-France (255-220) are observationally different. If FALSE, the function returns non-directed data. In non-directed data, France-Germany and Germany-France in the same year are the same observation. The standard here is to drop cases where the country code for the second observation is less than the country code for the first observation.

Value

create_dyadyears() takes state system membership data provided by either Correlates of War or Gleditsch-Ward and returns a dyad-year data frame.

References

Miller, Steven V. 2019. ``Create Country-Year and (Non)-Directed Dyad-Year Data With Just a Few Lines in R'' http://svmiller.com/blog/2019/01/create-country-year-dyad-year-from-country-data/

Author

Steven V. Miller

Examples

# \donttest{ # CoW is default, will include years beyond 2016 (most recent CoW update) create_dyadyears()
#> # A tibble: 2,063,670 x 3 #> ccode1 ccode2 year #> <dbl> <dbl> <int> #> 1 2 20 1920 #> 2 2 20 1921 #> 3 2 20 1922 #> 4 2 20 1923 #> 5 2 20 1924 #> 6 2 20 1925 #> 7 2 20 1926 #> 8 2 20 1927 #> 9 2 20 1928 #> 10 2 20 1929 #> # … with 2,063,660 more rows
# Gleditsch-Ward, include most recent years create_dyadyears(system="gw")
#> # A tibble: 2,029,660 x 3 #> gwcode1 gwcode2 year #> <dbl> <dbl> <int> #> 1 2 20 1867 #> 2 2 20 1868 #> 3 2 20 1869 #> 4 2 20 1870 #> 5 2 20 1871 #> 6 2 20 1872 #> 7 2 20 1873 #> 8 2 20 1874 #> 9 2 20 1875 #> 10 2 20 1876 #> # … with 2,029,650 more rows
# Gleditsch-Ward, don't include most recent years create_dyadyears(system="gw", mry=FALSE)
#> # A tibble: 1,939,354 x 3 #> gwcode1 gwcode2 year #> <dbl> <dbl> <int> #> 1 2 20 1867 #> 2 2 20 1868 #> 3 2 20 1869 #> 4 2 20 1870 #> 5 2 20 1871 #> 6 2 20 1872 #> 7 2 20 1873 #> 8 2 20 1874 #> 9 2 20 1875 #> 10 2 20 1876 #> # … with 1,939,344 more rows
# Gleditsch-Ward, don't include most recent years, directed = FALSE create_dyadyears(system="gw", mry=FALSE, directed = FALSE)
#> # A tibble: 969,677 x 3 #> gwcode1 gwcode2 year #> <dbl> <dbl> <int> #> 1 2 20 1867 #> 2 2 20 1868 #> 3 2 20 1869 #> 4 2 20 1870 #> 5 2 20 1871 #> 6 2 20 1872 #> 7 2 20 1873 #> 8 2 20 1874 #> 9 2 20 1875 #> 10 2 20 1876 #> # … with 969,667 more rows
# }