arranging multiple plots with cowplot cuts off statistics

Question

When arranging multiple plots from a plotlist with cowplot, the stat_compare_means values get cut off in the grid (see picture). When I am removing the plots titles it will still be cut off. Is there a way to fix this? Please find reproducible code below:

library(tidyverse)
library(ggplot2)
library(ggpubr)
library(cowplot)


plotlist = list()
u=3
for (i in 0:3) {
  single_plot <- iris %>%
    ggplot(aes(x = Species, y = Sepal.Width , group=Species)) + #create a plot, specify x,y, parameters
    geom_point(aes(shape = Species)) + # create a 
    stat_summary(fun = mean, # calculate SEM, specify type and width of the resulting bars
                 fun.min = function(x) mean(x) - sd(x)/sqrt(length(x)), #calculate ymin SEM
                 fun.max = function(x) mean(x) + sd(x)/sqrt(length(x)), #calculate ymax SEM
                 geom = 'errorbar',  width = 0.2) + #specify type of stat_summary and its size
    stat_summary(fun = mean, fun.min = mean, fun.max = mean, #calculate mean, specify type, width and size (fatten) of the resulting bars
                 geom = 'errorbar',  width = 0.4, size=1.2) +#specify type of stat_summary and its size
    labs(x = "x_label", y = "y_label") +#set the x- and y-axis labels
    ggtitle("plot_title")+#set the plot title
    theme_classic() +#adjust the basic size of the plot
    theme(
      legend.position = "none", #do not use a plot legend
    )+
    stat_compare_means(method="kruskal.test")
  plotlist <- append(plotlist, list(single_plot))
  i=i+1
}


plot_grid(plotlist = plotlist,
          labels = "AUTO"
)

Answer 1

increase the y axis scale and expand the limits

For this particular plot, I found this combination of parameters to work well.

+ scale_y_continuous(limits = c(2, 5), expand = c(0, 0.3))

Answer 2

I now figured out the solution. The y-axis has to be scaled using scale_y_continious with a relative expansion using expand(expand = expansion(mult = c(x_expasion, y_expansion). See reproducible code below.

library(tidyverse)
library(ggplot2)
library(ggpubr)
library(cowplot)


plotlist = list()
u=3
for (i in 0:3) {
  single_plot <- iris %>%
    ggplot(aes(x = Species, y = Sepal.Width , group=Species)) + #create a plot, specify x,y, parameters
    geom_point(aes(shape = Species)) + # create a 
    stat_summary(fun = mean, # calculate SEM, specify type and width of the resulting bars
                 fun.min = function(x) mean(x) - sd(x)/sqrt(length(x)), #calculate ymin SEM
                 fun.max = function(x) mean(x) + sd(x)/sqrt(length(x)), #calculate ymax SEM
                 geom = 'errorbar',  width = 0.2) + #specify type of stat_summary and its size
    stat_summary(fun = mean, fun.min = mean, fun.max = mean, #calculate mean, specify type, width and size (fatten) of the resulting bars
                 geom = 'errorbar',  width = 0.4, size=1.2) +#specify type of stat_summary and its size
    scale_y_continuous(expand = expansion(mult = c(0,.1)))  +#create continouos y scale and set relative expansion 
    labs(x = "x_label", y = "y_label") +#set the x- and y-axis labels
    ggtitle("plot_title")+#set the plot title
    theme_classic() +#adjust the basic size of the plot
    theme(
      legend.position = "none", #do not use a plot legend
    )+
    stat_compare_means(method="kruskal.test")
  plotlist <- append(plotlist, list(single_plot))
  i=i+1
}


print(plot_grid(plotlist = plotlist,
          labels = "AUTO"
))