Using geom_pointrange() to plot means and standard errors - r

Question

I have three groups (categorical variable) who completed a test and a dataframe with the mean and standard error on the test per group. I would like to plot their means as a single point in the plot accompanied by a short horizontal line indicating the standard error (i.e., error bars). I'm using R with ggplot2.
My x-axis represents all the possible scores in the test (from -218 to 218) and the groups are plotted on the y-axis (I used coord_flip() for this).
I was able to create the graph but the standard error lines don't show up, so I don't know what I'm doing wrong. I think it has to do with my use of geom_pointrange(), but I have no idea what I'm supposed to change.
This is my code:
ggplot(descriptive_blp_data) +
aes(x = group, y = mean_blp, colour = group, size = 5) +
geom_pointrange(aes(ymin = mean_blp - se_blp, ymax = mean_blp + se_blp), width=.2,
position=position_dodge(.9)) +
scale_color_manual(
values = list(
Group_2 = "#9EBCDA",
Group_3 = "#8856A7",
Group_1 = "#E0ECF4"
)
) +
labs(y = "Mean BLP score (SE)") +
coord_flip() +
theme_classic() +
theme(legend.position = "none", axis.title.y = element_blank()) +
ylim(-218, 218)
And this is my graph so far:

Answer 1

It is easier to check this, if you can provide the actual dataframe descriptive_blp_data. Running your code with some arbitrary dataset does work as intended and produces error bars, so there is nothing really wrong with the ggplot part.
There may be a few reasons why this does not work with your actual dataset - maybe the standard errors are too small to show up with a point size of 5?
descriptive_blp_data <- data.frame(
"group" = c("Group_3", "Group_2", "Group_1"),
"mean_blp" = c(150, 50, -50),
"se_blp" = c(40, 20, 30)
)
library(ggplot2)
ggplot(descriptive_blp_data) +
aes(x = group, y = mean_blp, colour = group, size = 5) +
geom_pointrange(aes(ymin = mean_blp - se_blp, ymax = mean_blp + se_blp), width=.2,
position=position_dodge(.9)) +
scale_color_manual(
values = list(
Group_2 = "#9EBCDA",
Group_3 = "#8856A7",
Group_1 = "#E0ECF4"
)
) +
labs(y = "Mean BLP score (SE)") +
coord_flip() +
theme_classic() +
theme(legend.position = "none", axis.title.y = element_blank()) +
ylim(-218, 218)