Add boxes with descriptive annotations to y-axis in ggplot2

Question

I"M trying to add another label or description to my Y axis. I attached a picture for reference for what I'm trying to accomplish. I can't find anything that describes how to add additional elements to an axis. It the "Good" and "Bad" boxes beside the Y axis that I"m trying to incorporate into my ggplot. Thanks!

enter image description here

Answer 1

One approach to achieve this is by using patchwork. You can set up the annotations of the y-axis as a second ggplot and glue it to your main plot using patchwork. Try this:

library(ggplot2)
library(patchwork)
library(dplyr)

p1 <- tibble(x = 1:10, y = 1:10) %>% 
  ggplot(aes(x, y)) +
  geom_point() +
  scale_y_reverse(breaks = seq(1, 10)) +
  labs(y = NULL)

p2 <- tibble(ymin = c(0, 4), ymax = c(4, 10), fill = c("bad", "good")) %>% 
  ggplot() +
  geom_rect(aes(xmin = 0, xmax = 1, ymin = ymin, ymax = ymax, fill = fill)) +
  geom_text(aes(x = .5, y = (ymin  + ymax) / 2, label = fill), angle = 90) +
  scale_y_reverse(breaks = seq(1, 10), expand = expansion(mult = c(0, 0))) +
  scale_x_continuous(breaks = c(0), expand = expansion(mult = c(0, 0))) +
  guides(fill = FALSE) +
  theme_void()

p2 + p1 + plot_layout(widths = c(1, 9))

^{Created on 2020-05-28 by the reprex package (v0.3.0)}