R : confidence interval being partially displayed with ggplot2 (using geom_smooth())

Question

I have the following simple R code:

disciplines <- c(\"A\",\"C\",\"B\",\"D\",\"E\")
# To stop ggplot from imposing alphabetical ordering on x-axis
discipl         


        

Answer 1

For the first three segments of the confidence interval, the top end of the range is at least partially out of bounds (the bounds being [-1, 1], not the slightly expanded range on the axes). ggplot's default behavior is to not display any object that is partially out of bounds. You can fix this by adding oob=scales::rescale_none to scale_y_continuous:

library(scales)
graph <- ggplot(df.m, aes(group=1,disciplines,value,colour=variable,shape=variable)) +
         geom_point() +
         geom_smooth(stat="smooth", method=loess, level=0.95) +
         scale_x_discrete(name="Disciplines") +
         scale_y_continuous(limits=c(-1,1), name="Measurement", oob=rescale_none)

Answer 2

A better documented, and perhaps more intuitive, solution would be to simply use coord_cartesian:

ggplot(df.m, aes(group=1,disciplines,value,colour=variable,shape=variable)) +
         geom_point() +
         geom_smooth(stat="smooth", method=loess, level=0.95) +
         scale_x_discrete(name="Disciplines") +
         coord_cartesian(ylim = c(-1,1))