Quantile-quantile plots (Q-Q plots) are a powerful way of visually diagnosing distributional assumptions of random variables. Q-Q plots have been implemented in various forms in R, starting with qqplot and qqline functions in the base package. However, the functionality within the ggplot2 package is restricted to the function geom_qq, which is a geom object only concerned with the placement of points in a Q-Q plot following a certain distribution. The main objective of this project is to provide ggplot2 add-ons that enable the functionality for the drawing of a Q-Q line, different confidence regions methods, and the rotation of the Q-Q plot, all in the form of geoms. The expected outcomes are: (1) an R package with the said add-ons implemented as ggplot2 geoms, well documented and fully functional; (2) a set of examples, documented in a vignette, and (3) a Shiny app interactvely highlighting the functionalities of the implementations, to be embedded in the vignette documentation.


Alexandre Almeida


  • Adam Loy
  • Heike Hofmann