# ggsignif v0.6.0

0

0th

Percentile

## Significance Brackets for 'ggplot2'

Enrich your 'ggplots' with group-wise comparisons. This package provides an easy way to indicate if two groups are significantly different. Commonly this is shown by a bracket on top connecting the groups of interest which itself is annotated with the level of significance (NS, *, **, ***). The package provides a single layer (geom_signif()) that takes the groups for comparison and the test (t.test(), wilcox.text() etc.) as arguments and adds the annotation to the plot.

# ggsignif

## Description

This package provides an easy way to indicate if two groups are significantly different. Commonly this is shown by a bar on top connecting the groups of interest which itself is annotated with the level of significance (NS, *, **, ***). The package provides a single layer (geom_signif) that takes the groups for comparison and the test (t.test, wilcox etc.) and adds the annotation to the plot.

## Example

Install package

install.packages("ggsignif")

# Or for the latest development version
devtools::install_github("const-ae/ggsignif")


Plot significance

library(ggplot2)
library(ggsignif)
ggplot(mpg, aes(class, hwy)) +
geom_boxplot() +
geom_signif(comparisons = list(c("compact", "midsize"), c("minivan", "suv")),
map_signif_level = TRUE, textsize=6) +
ylim(NA, 48)


Setting the precise location

This is important if you use position="dodge", because in that case I cannot calculate the correct position of the bars automatically.

# Calculate annotation
anno <- t.test(iris[iris$Petal.Width > 1 & iris$Species == "versicolor", "Sepal.Width"],
iris[iris$Species == "virginica", "Sepal.Width"])$p.value

# Make plot with custom x and y position of the bracket
ggplot(iris, aes(x=Species, y=Sepal.Width, fill=Petal.Width > 1)) +
geom_boxplot(position="dodge") +
geom_signif(annotation=formatC(anno, digits=1),
y_position=4.05, xmin=2.2, xmax=3,
tip_length = c(0.2, 0.04))


Sometimes one needs to have a very fine tuned ability to set the location of the the significance bars in combination with facet_wrap or facet_grid. In those cases it you can set the flag manual=TRUE and provide the annotations as a data.frame:

annotation_df <- data.frame(color=c("E", "H"),
start=c("Good", "Fair"),
end=c("Very Good", "Good"),
y=c(3.6, 4.7),
label=c("Comp. 1", "Comp. 2"))

annotation_df
#>   color start       end   y   label
#> 1     E  Good Very Good 3.6 Comp. 1
#> 2     H  Fair      Good 4.7 Comp. 2

ggplot(diamonds, aes(x=cut, y=carat)) +
geom_boxplot() +
geom_signif(data=annotation_df,
aes(xmin=start, xmax=end, annotations=label, y_position=y),
textsize = 3, vjust = -0.2,
manual=TRUE) +
facet_wrap(~ color) +
ylim(NA, 5.3)


You can ignore the warning about the missing aesthetics.

For further details go the CRAN page and check the examples in the vignette.

## Maintenance

This package is provided as is and I currently don't have any plans and the capacity to add any new features to it. If there is nonetheless a feature which you would like to see in the package, you are always welcome to submit pull request, which I will try to address as soon as possible.