Ajust variable order and color in forest plot (ggplot2)

Question

I have adapted the solution to align forest plot and a table from this post:

how to align table with forest plot (ggplot2)

Here is my code:

library(dplyr, warn = FALSE)
library(ggplot2)
library(patchwork)

tester <- data.frame(
  treatmentgroup = c("Education Continuous", "0", "1-4", 
                     "5-8", ">8"),
  or = c(0.914, 0.961, 0.709, 0.523, 0.457),
  low_ci = c(0.894, 0.793, 0.577, 0.389, 0.339),
  up_ci = c(0.935, 1.166, 0.871, 0.708, 0.616),
  OR_ci = c(
    "0.914 (0.894; 0.935)", "0.961 (0.793; 1.166)", "0.709 (0.577; 0.871)", 
    "0.523 (0.389; 0.708)", "0.457 (0.339; 0.616)"),
  ci = c(
    "0.894; 0.935",
    "0.793; 1.166",
    "0.577; 0.871",
    "0.389; 0.708",
    "0.339; 0.616"),
  no = c(1, 2, 3, 4, 5)
)


forest <- ggplot(
  data = tester,
  aes(x = treatmentgroup, y = or, ymin = low_ci, ymax = up_ci)) +
  geom_pointrange(aes(col = treatmentgroup)) +
  geom_hline(yintercept = 1, colour = "black") +
  xlab("") +
  ylab("OR (95% CI)") +
  geom_errorbar(aes(ymin = low_ci, ymax = up_ci, col = treatmentgroup), width = 0, cex = 1) +
  theme_classic() +
  theme(
    panel.background = element_blank(), strip.background = element_rect(colour = NA, fill = NA),
    strip.text.y = element_text(face = "bold", size = 12),
    panel.grid.major.y = element_line(colour = col_grid, size = 0.5),
    strip.text = element_text(face = "bold"),
    panel.border = element_rect(fill = NA, color = "black"),
    legend.position = "none",
    axis.text = element_text(face = "bold"),
    axis.title = element_text(face = "bold"),
    plot.title = element_text(face = "bold", hjust = 0.5, size = 13)
  ) +
  coord_flip()

dat_table <- tester %>%
  select(treatmentgroup, OR_ci) %>%
  tidyr::pivot_longer(c(OR_ci), names_to = "stat") %>%
  mutate(stat = factor(stat, levels = "OR_ci"))

table_base <- ggplot(dat_table, aes(stat, treatmentgroup, label = value)) +
  geom_text(size = 3) +
  scale_x_discrete(position = "top", labels = "OR (95% CI)") +
  labs(y = NULL, x = NULL) +
  theme_classic() +
  theme(
    strip.background = element_blank(),
    panel.grid.major = element_blank(),
    panel.border = element_blank(),
    axis.line = element_blank(),
    axis.text.y = element_blank(),
    axis.text.x = element_text(size = 12),
    axis.ticks = element_blank(),
    axis.title = element_text(face = "bold"),
  )

forest + table_base + plot_layout(widths = c(10, 4))

However, my graph ends up with the categories out of order. How can I adjust the order to this one: Education Continuous, 0, 1-4, 5-8, and >8?

I tried factor(tester$treatmentgroup) but it did not work.

Also, how can I make all the categories the same color (black, for example) instead of one each color? I tried eliminating the line geom_pointrange(aes(col = treatmentgroup)) + but it does not work.

score 1 · Accepted Answer · answered Nov 09 '22 at 18:08

You're right that you can convert treatmentgroup to a factor, you just need to specify the levels. Try running this code before you generate your plots with ggplot().

tester <- tester %>%
  mutate(treatmentgroup = factor(treatmentgroup,
                                 levels = c(">8", "5-8", "1-4", "0", "Education Continuous")))

Ajust variable order and color in forest plot (ggplot2)

1 Answers1