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Plot two-way interaction graphs for all IV pair and DV combinations

Source: R/GLM_ANOVA_PLOT.R
plot_interaction.Rd

For every unique pair of independent variables (IV1 x IV2) and every dependent variable (DV), produces a line-and-point interaction plot with group means on the y-axis. IV1 levels appear on the x-axis (flipped) and IV2 levels are represented by colour and line group. Optional error bars and per-group sample size annotations are included.

When the number of combinations exceeds four times the available CPU cores the plots are produced in parallel via future.apply, otherwise sequentially.

Usage

plot_interaction(
  df,
  dv,
  iv,
  base_size = 20,
  type = "se",
  order_factor = TRUE,
  title = "",
  note = ""
)

Arguments

df

A data frame containing both the independent and dependent variables.

dv

Integer vector of column indices for the continuous dependent variables.

iv

Integer vector of column indices for the categorical independent variables. The columns are coerced to factors automatically.

base_size

Base font size in pt passed to theme_bw. Default 20.

type

Type of error bar to display. One of "se" (standard error), "ci" (95% confidence interval), "sd" (standard deviation), or "" (no error bars). Default "se".

order_factor

Logical. If TRUE factor levels on the x-axis are sorted by the group mean of the DV (descending). Default TRUE.

title

Character. Plot title applied to every panel. Default "".

note

Character. Caption / footnote appended to every panel. Default "".

Value

A named list with three elements:

  • plot_data — named list of summary data frames (one per IV1-IV2-DV combination) as returned by Rmisc::summarySE.

  • plot_data_df — single data frame combining all summary data frames row-wise.

  • plots — named list of ggplot objects (one per combination).

All list elements are named "iv1_iv2_dv".

Examples

# Single DV, two IVs
plot_interaction(df = mtcars, dv = 2, iv = 8:9, base_size = 20, type = "se")



# Multiple DVs, two IVs
plot_interaction(df = mtcars, dv = 2:3, iv = 8:9, base_size = 20, type = "se")




plot_interaction(df = mtcars, dv = 2:3, iv = 8:9, base_size = 20, type = "ci")




plot_interaction(df = mtcars, dv = 2:3, iv = 9:10, base_size = 20, type = "sd")





# No error bars, unordered factor axis
plot_interaction(df = mtcars, dv = 2, iv = 9:10, base_size = 20, type = "",
                 order_factor = FALSE)