add_sdp_gdp() allows you to add estimated GDP and "surplus"
domestic product data from a 2020 analysis published in
International Studies Quarterly by Anders, Fariss, and Markowitz.
Value
add_sdp_gdp() takes a (dyad-year, leader-year, leader-dyad-year,
state-year) data frame and adds information about the estimated gross
domestic product (in 2011 USD) for that year, the estimated population
in that year, the GDP per capita in that year, and what Anders, Fariss
and Markowitz term the "surplus domestic product" in that year. If the
data are dyad-year (leader-dyad-year), the function adds eight total
columns for the first state (i.e. ccode1) and the second state
(i.e. ccode2) for all these estimates. If the data are state-year
(or leader-year), the function returns four additional columns to the
original data that contain that same information for a given state in
a given year.
Details
The function leans on attributes of the data that are provided by one of the "create" functions. Make sure a recognized function (or data created by that function) appear at the top of the proverbial pipe. Users will also want to note that the underlying function access two different data sets. It appears that the results published in the International Studies Quarterly used Correlates of War classification, but a follow-up repository on Github uses Gleditsch-Ward classification. The extent to which these estimates are generated by simulation, it does mean the estimates will be slightly different across both data sets even for common observations (e.g. the United States in 1816).
Because these are large nominal numbers, the estimates have been log-transformed. Users can always exponentiate these if they choose. Researchers can use these data to construct reasonable estimates of surplus GDP per capita, but must exponentiate the underlying variables before doing this.
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.
References
Anders, Therese, Christopher J. Fariss, and Jonathan N. Markowitz. 2020. "Bread Before Guns or Butter: Introducing Surplus Domestic Product (SDP)" International Studies Quarterly 64(2): 392--405.
Examples
# just call `library(tidyverse)` at the top of the your script
library(magrittr)
cow_ddy %>% add_sdp_gdp()
#> # A tibble: 2,139,270 × 11
#> ccode1 ccode2 year wbgdp2011est1 wbpopest1 sdpest1 wbgdppc2011est1
#> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 2 20 1920 27.6 18.4 27.5 9.19
#> 2 2 20 1921 27.6 18.5 27.5 9.18
#> 3 2 20 1922 27.7 18.5 27.6 9.21
#> 4 2 20 1923 27.8 18.5 27.7 9.26
#> 5 2 20 1924 27.8 18.5 27.7 9.30
#> 6 2 20 1925 27.9 18.5 27.8 9.32
#> 7 2 20 1926 27.9 18.5 27.8 9.34
#> 8 2 20 1927 27.9 18.6 27.8 9.35
#> 9 2 20 1928 27.9 18.6 27.8 9.36
#> 10 2 20 1929 27.9 18.6 27.8 9.35
#> # ℹ 2,139,260 more rows
#> # ℹ 4 more variables: wbgdp2011est2 <dbl>, wbpopest2 <dbl>, sdpest2 <dbl>,
#> # wbgdppc2011est2 <dbl>
create_stateyears() %>% add_sdp_gdp()
#> Joining with `by = join_by(ccode, year)`
#> # A tibble: 17,121 × 7
#> ccode statenme year wbgdp2011est wbpopest sdpest wbgdppc2011est
#> <dbl> <chr> <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 2 United States of Ame… 1816 23.6 15.9 22.9 7.66
#> 2 2 United States of Ame… 1817 23.6 16.0 22.9 7.64
#> 3 2 United States of Ame… 1818 23.6 16.0 22.9 7.64
#> 4 2 United States of Ame… 1819 23.7 16.0 23.0 7.66
#> 5 2 United States of Ame… 1820 23.7 16.1 23.0 7.66
#> 6 2 United States of Ame… 1821 23.8 16.1 23.1 7.68
#> 7 2 United States of Ame… 1822 23.8 16.1 23.1 7.70
#> 8 2 United States of Ame… 1823 23.8 16.1 23.1 7.69
#> 9 2 United States of Ame… 1824 23.9 16.2 23.2 7.69
#> 10 2 United States of Ame… 1825 23.9 16.2 23.3 7.72
#> # ℹ 17,111 more rows
create_stateyears(system = "gw") %>% add_sdp_gdp()
#> Joining with `by = join_by(gwcode, year)`
#> # A tibble: 18,637 × 7
#> gwcode statename year wbgdp2011est wbpopest sdpest wbgdppc2011est
#> <dbl> <chr> <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 2 United States of Am… 1816 23.6 15.9 22.8 7.66
#> 2 2 United States of Am… 1817 23.6 16.0 22.8 7.64
#> 3 2 United States of Am… 1818 23.6 16.0 22.9 7.64
#> 4 2 United States of Am… 1819 23.7 16.0 22.9 7.66
#> 5 2 United States of Am… 1820 23.7 16.1 23.0 7.66
#> 6 2 United States of Am… 1821 23.8 16.1 23.0 7.68
#> 7 2 United States of Am… 1822 23.8 16.1 23.1 7.70
#> 8 2 United States of Am… 1823 23.8 16.1 23.1 7.69
#> 9 2 United States of Am… 1824 23.9 16.2 23.2 7.69
#> 10 2 United States of Am… 1825 23.9 16.2 23.2 7.72
#> # ℹ 18,627 more rows