Add GDP data to a state panel — add

Joins GDP data onto an existing state panel. The coding system ("cow" or "gw") and year range are detected automatically from the panel.

Usage

add_gdp(panel, dataset = c("gapminder", "fariss"))

Arguments

panel: A data frame produced by build_states_panel(), containing a cow or gw column and a year column.
dataset: Dataset to use: "gapminder" (default) or "fariss". See load_gdp_data() for details and added columns.

Value

The input panel with GDP columns added via left join.

References

Gapminder. (2024). GDP per capita in constant PPP dollars. https://www.gapminder.org/gdp-per-capita/

Fariss, C. J., Anders, T., Markowitz, J. N., & Barnum, M. (2022). New estimates of over 500 years of historic GDP and population data. Journal of Conflict Resolution, 66(3), 553-591. doi:10.1177/00220027211054432

Examples

panel <- build_states_panel(1990, 2010, coding_system = "cow") |>
  add_gdp()

panel <- build_states_panel(1900, 2010, coding_system = "cow") |>
  add_gdp(dataset = "fariss")