In williazo/ggplot.spaghetti:

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.path = "README-"
)

ggplot.spaghetti

The goal of ggplot.spaghetti is to aid preliminary data investigation into longitudinal/time-series data through visualization. By being able to create plots using different grouping variable, the investigator can have a better idea which variables may be worthwhile to control or include in a hypothesis test. Also these images can be used to help rely to other non-statistical collaborators the trends from a mixed-effects or other type of longitudinal model.

Installation

You can install ggplot.spaghetti from github with:

# install.packages("devtools")
devtools::install_github("williazo/ggplot.spaghetti")

Example

This is an example using the Orthodont data set from the nlme package. Children were measured at 8, 10, 12, and 14 years to determine the distance from the pituitary to the pterygomaxillary fissure in millimeters. We can group these time measurements by Gender, and I have also created another binary variable, Race, to highlight the ability to look at multiple grouping variables at the same time.

library(ggplot.spaghetti)
library(nlme)
data("Orthodont")
Orthodont = data.frame(Orthodont, Race = rep(ifelse(rbinom(n = 27, size = 1, prob = 0.5)==0, "White", "Non-White"), each = 4))
attach(Orthodont)

#specifying just group
ortho_plot_group <- ggplot_spaghetti(y = distance, id = Subject, time = age,
                               alpha = 0.3, group = Sex, method = "lm")+
  xlab("Age (yrs.)")+
  ylab("Distance")+
  scale_color_grey(name = "Gender", start = 0.0, end = 0.5)+
  scale_linetype_manual(name = "Gender", values = c("dashed", "solid"))
ortho_plot_group

#specifying just wrap
ortho_plot_wrap <- ggplot_spaghetti(y = distance, id = Subject, time = age,
                               alpha = 0.3, wrap = Race, method = "loess")+
  xlab("Age (yrs.)")+
  ylab("Distance")+
  scale_color_grey(name = "Race", start = 0.0, end = 0.5)+
  scale_linetype_manual(name = "Race", values = c("dashed", "solid"))
ortho_plot_wrap

#specifying both group and wrap
ortho_plot <- ggplot_spaghetti(y = distance, id = Subject, time = age,
                               alpha = 0.3, group = Sex, wrap = Race,
                               method = "glm")+
  xlab("Age (yrs.)")+
  ylab("Distance")+
  scale_color_grey(name = "Gender", start = 0.0, end = 0.5)+
  scale_linetype_manual(name = "Race", values = c("dashed", "solid"))
ortho_plot