gerda (version 0.5.0)

add_gerda_census: Add Census 2022 Data to GERDA Election Data

Description

Convenience function to merge Zensus 2022 municipality-level data with GERDA election data. The census provides a cross-sectional snapshot (2022), so the same values are attached to all election years.

The function works with both municipality-level and county-level election data:

• Municipality-level data: Direct merge using 8-digit AGS codes

• County-level data: Census data is aggregated to the county level (population-weighted means for shares, sums for counts) before merging

Usage

add_gerda_census(election_data)

Value

The input data frame with additional census columns appended. The number of rows remains unchanged (left join).

Arguments

election_data

A data frame containing GERDA election data. Must contain either an ags column (municipality level) or a county_code column (county level).

Details

Required Columns

The input data must contain one of:

• ags: 8-digit municipal code for municipality-level data

• county_code: 5-digit county code for county-level data

Merge Behavior

Since the census is a 2022 cross-section, census values are the same for all election years. The merge is on geography only (no year join).

For county-level data, municipality-level census data is first aggregated:

• Share variables: Population-weighted means

• Count variables (population_census22, total_dwellings_census22): Sums

• Other variables (avg_household_size_census22, avg_rent_per_m2_census22): Population-weighted means

See Also

• gerda_census for direct access to the census data

• gerda_census_codebook for variable descriptions

Examples

if (FALSE) {
library(gerda)

# Municipality-level merge
muni_data <- load_gerda_web("federal_muni_harm_21") |>
  add_gerda_census()

# County-level merge (aggregated from municipalities)
county_data <- load_gerda_web("federal_cty_harm") |>
  add_gerda_census()
}