state_min_wage.R

library(fredr)
library(tidyverse)
library(geofacet)
library(ggrepel)
library(ggtext)

set.seed(42) # For reproducibility

# Prepare state series IDs
state_ids <- c(
  map_chr(state.abb, ~ paste0("STTMINWG", .x)), 
  "STTMINWGDC"
) %>% 
  setdiff(c(
    "STTMINWGAL", "STTMINWGLA", 
    "STTMINWGMS", "STTMINWGSC", 
    "STTMINWGTN"
  ))

# Fetch minimum wage data for each state
min_wage <- map_dfr(
  state_ids, 
  ~ fredr(
    series_id = .x, 
    observation_start = as.Date("2000-01-01"), 
    observation_end = Sys.Date()
  ) %>% 
    mutate(st = str_sub(.x, -2))
)

# Fetch federal minimum wage data
fed_mw <- fredr(
  series_id = "FEDMINNFRWG", 
  observation_start = as.Date("2000-01-01"), 
  observation_end = Sys.Date()
) %>% 
  mutate(st = "FED")

# Combine state and federal minimum wage data
min_wage_full <- min_wage %>% 
  full_join(
    expand_grid(
      st = state.abb, 
      date = seq.Date(as.Date("2000-01-01"), Sys.Date(), by = "year")
    ), 
    by = c("st", "date")
  ) %>% 
  left_join(
    fed_mw %>% 
      select(date, value_fed = value), 
    by = "date"
  ) %>% 
  mutate(value = coalesce(value, value_fed)) %>% 
  select(date, st, value, value_fed) %>% 
  arrange(st, date)

# Prepare data for area step plot
min_wage_area_step <- min_wage_full %>% 
  transmute(
    date, st, value, 
    source = "new"
  ) %>% 
  bind_rows(
    min_wage_full %>% 
      transmute(
        date, st, 
        value = lag(value), 
        source = "old"
      )
  ) %>% 
  arrange(date, st, source)

# Plotting
min_wage_full %>% 
  ggplot(aes(date, value)) +
  geom_ribbon(
    aes(x = date, ymin = 0, ymax = value), 
    alpha = 0.6, 
    fill = "#460073", 
    data = min_wage_area_step
  ) +
  geom_step(aes(date, value_fed), color = "black", linetype = "dashed") +
  labs(
    x = "Year", 
    y = "Min Wage", 
    title = "USA State Minimum Wage over Time", 
    caption = "Source:\nfred.stlouisfed.org\ndol.gov/agencies/whd/minimum-wage"
  ) +
  geom_text_repel(
    aes(label = text), 
    size = 3.5, 
    hjust = .5, 
    min.segment.length = 0, 
    nudge_y = 5, 
    data = tibble(
      date = as.Date("2016-01-01"), 
      value = 7.25, 
      st = factor("WI", levels = state.abb), 
      text = "Fed Min\nWage"
    )
  ) +
  facet_geo(~ st) +
  scale_x_date(date_labels = "'%y") +
  scale_y_continuous(labels = scales::dollar) +
  coord_cartesian(clip = "off") +
  theme_minimal() +
  theme(
    panel.grid.minor = element_blank(),
    axis.ticks = element_blank(),
    plot.title = element_markdown(
      face = "bold",
      size = 20,
      hjust = 0.5
    ),
    plot.title.position = "plot",
    plot.subtitle = element_markdown(
      size = 14,
      hjust = 0
    ),
    plot.caption = element_markdown(
      size = 9,
      hjust = 1,
      margin = margin(t = 15)
    ),
    plot.caption.position = "plot",
    axis.title = element_markdown(
      size = 10,
    ),
    axis.text = element_text(
      size = 9,
    ),
    axis.text.x = element_text(
      margin = margin(5, b = 10)
    ),
    axis.title.y = element_text(
      margin = margin(r = 20)
    ),
    plot.margin = margin(25, 25, 10, 25)
  )