This data contain Kieth’s Poole DW-NOMINATE measure of legislator ideology. Keith worked with various coauthors through the years, but Jeff Lewis now maintains the data, which you can find here.

These data contain the first dimmensions of the DW-NOMINATE scores from Republican and Democrat members of the House from the 100th to the most recent Congress.

The data set is at the member-Congress level, so that each row of the data set represents one election in a particular Congress (e.g., Nancy Pelosi in the 110th Congress).

For details on the raw data, see the codebook for the raw data.

Load Data

# load packages
library(tidyverse)

# load data
nominate_df <- read_rds("nominate.rds")

# quick look at data
glimpse(nominate_df)
## Observations: 7,080
## Variables: 7
## $ congress <int> 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100...
## $ chamber  <chr> "House", "House", "House", "House", "House", "House",...
## $ state    <chr> "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AK", "AZ",...
## $ district <int> 2, 4, 3, 5, 6, 1, 7, 1, 2, 3, 5, 4, 1, 3, 1, 4, 2, 36...
## $ party    <fct> Republican, Democrat, Democrat, Democrat, Democrat, R...
## $ name     <chr> "DICKINSON, William Louis", "BEVILL, Tom", "NICHOLS, ...
## $ ideology <dbl> 0.398, -0.213, -0.042, -0.175, -0.060, 0.373, -0.085,...

Variable Descriptions

congress

  • Coding: The number of the Congress
  • Range: 100th to 114th
  • Type: integer

state

  • Coding: The two-letter abbreviation of name of the member’s state.
  • Type: character

congressional_district

  • Coding: The number of the member’s Congressional district.
  • Type: integer

party

  • Coding: The member’s partisan affiliation. Members not affiliated with the Democratic or Republican Party are dropped from this data set.
  • Type: character
  • Values:
    • "Republican"
    • "Democrat"

ideology

  • Coding: The first dimmension of the two-dimmenisonal DW-NOMINATE score. It is static over a member’s career in Congress. Values near zero indicate a moderate. More negative values indicate a more liberal representative. More positive values indicate a more conservative representative.
  • Type: double
# create a df with only the 114th congress
nominate114_df <- filter(nominate_df, congress == 114) 

# a histogram of the 114th congress
ggplot(nominate114_df, aes(x = ideology, fill = party)) + 
  geom_histogram(alpha = 0.5, position = "identity") + 
  scale_fill_manual(values = c("blue", "red")) + 
  labs(title = "Ideology in the 114th Congress")
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

# 5 most conservative members from 114th congress
top_n(nominate114_df, 5, ideology)
# 5 most liberal members from 114th congress
top_n(nominate114_df, 5, -ideology)