Create the plots to motivate Writing Assignment 1 for POLS 209 (Summer 2017).

wa1-plots.R

# remember to set working directory!

# load packages
library(ggplot2)
library(dplyr)

# load data
d <- readRDS("data/state-legislators.rds")

# quick look at data
tibble::glimpse(d)

# remove independents (not a lot of useful information here)
d <- subset(d, party != "Independent")

# calculate the average and SD within each party, state, and year
smry <- summarize(group_by(d, party, state, year), 
                  average = mean(ideology_score),
                  sd = sd(ideology_score))

# plot the average for each state over time
ggplot(smry, aes(x = year, y = average, color = party)) + 
  geom_line() + 
  facet_wrap(~ state) + 
  labs(x = "Year", 
       y = "Average Ideology Score", 
       color = "Party") + 
  theme_bw() + 
  scale_color_manual(values = c("blue", "red"))  # improve coloring of parties

# plot the SD for each state over time
ggplot(smry, aes(x = year, y = sd, color = party)) + 
  geom_line() + 
  facet_wrap(~ state) + 
  labs(x = "Year", 
       y = "SD of Ideology Scores", 
       color = "Party") + 
  theme_bw() + 
  scale_color_manual(values = c("blue", "red"))  # improve coloring of parties