Making APA Tables with the gt Package

Install gt and load key packages

You can install gt easily: install.packages("gt").

Here are the libraries we will need:

library(tidyverse)
library(gt)

Create a Basic gt table

mtcars %>%
  slice(1:5) %>%
  gt()

Style the Borders

All APA tables have a black top border, a black border at the bottom of the column header, and a black bottom border. We can use the following code to recreate that look, as well as set the width and make the font size consistent with the table body:

mtcars %>%
  slice(1:5) %>%
  gt() %>%
  tab_options(
    # hide the top-most border
    table.border.top.color = "white",
    # make the title size match the body text
    heading.title.font.size = px(16),
    # change the column labels section
    column_labels.border.top.width = 3,
    column_labels.border.top.color = "black", 
    column_labels.border.bottom.width = 3,
    column_labels.border.bottom.color = "black",
    # change the bottom of the body
    table_body.border.bottom.color = "black",
    # hide the bottom-most line or footnotes
    # will have a border
    table.border.bottom.color = "white",
    # make the width 100%
    table.width = pct(100),
    table.background.color = "white"
  )

This is good, but it’s not perfect. We still have to deal with text centering, row striping, and internal borders, not to mention titling, adding a footnote, and, if needed, italcizing specific column labels.

One issue that I have not figured out is how to control the thickness of the black borders. Right now, for column_labels.border.top.width, the width must be set to = 3 before any color changes. I have opened this as an issue on Github.

Styling the Table Body

mtcars %>%
  slice(1:5) %>%
  gt() %>%
  tab_options(
    table.border.top.color = "white",
    heading.title.font.size = px(16),
    column_labels.border.top.width = 3,
    column_labels.border.top.color = "black",
    column_labels.border.bottom.width = 3,
    column_labels.border.bottom.color = "black",
    table_body.border.bottom.color = "black",
    table.border.bottom.color = "white",
    table.width = pct(100),
    table.background.color = "white"
  ) %>%
  # center column text
  cols_align(align="center") %>%
  # set table style
  tab_style(
    style = list(
      # remove horizontal lines
      cell_borders(
        sides = c("top", "bottom"),
        color = "white",
        weight = px(1)
      ),
      #center text
      cell_text(
        align="center"
      ),
    # remove row striping in Markdown documents
    cell_fill(color = "white", alpha = NULL)
      ),
      #do this for all columns and rows
    locations = cells_body(
      columns = everything(),
      rows = everything()
    ))

This is looking very close to an APA table. However, that is a lot of code to get the basic APA look and feel. Can we simplify it?

Create an apa() Function

The following will create an APA function that creates the basic APA table layout and includes the stylization for a title. It’s two arguments would be apa(x, title) where x = a data frame, and title is a string in quotes.

apa <- function(x, title = " ") {
  gt(x) %>%
  tab_options(
    table.border.top.color = "white",
    heading.title.font.size = px(16),
    column_labels.border.top.width = 3,
    column_labels.border.top.color = "black",
    column_labels.border.bottom.width = 3,
    column_labels.border.bottom.color = "black",
    table_body.border.bottom.color = "black",
    table.border.bottom.color = "white",
    table.width = pct(100),
    table.background.color = "white"
  ) %>%
  cols_align(align="center") %>%
  tab_style(
    style = list(
      cell_borders(
        sides = c("top", "bottom"),
        color = "white",
        weight = px(1)
      ),
      cell_text(
        align="center"
      ),
      cell_fill(color = "white", alpha = NULL)
      ),
    locations = cells_body(
      columns = everything(),
      rows = everything()
    )
  ) %>%
    #title setup
    tab_header(
    title = html("<i>", title, "</i>")
  ) %>%
  opt_align_table_header(align = "left")
}

Let’s try it out:

mtcars %>%
  slice(1:5) %>%
  apa("Fuel consumption and aspects of automobile design and performance for 32 automobiles (1973-74 models)")

Add a Footnote

If we wanted to add a note, we would do so using an additional gt function:

mtcars %>%
  slice(1:5) %>%
  apa("Fuel consumption and aspects of automobile design and performance for 32 automobiles (1973-74 models)") %>%
  tab_footnote(
    #footnote text
    footnote = "This is a footnote.",
    # add to the column labels section
    locations = cells_column_labels(
      # add to the "mpg" column
      columns = vars(mpg))
  )

Italicize Column Text

In many APA tables, statical indicators such as p, M or n are italicized. We can do that here in the following manner:

mtcars %>%
  slice(1:5) %>%
  apa("Fuel consumption and aspects of automobile design and performance for 32 automobiles (1973-74 models)") %>%
    tab_footnote(
    footnote = "This is a footnote.",
    locations = cells_column_labels(
      columns = vars(mpg))
  ) %>%
  # add an additional table style
  tab_style(
    style = list(
      # change the text
      cell_text(style="italic")
  ),
  # specify the column
  locations = cells_column_labels(
      columns = vars(cyl)
      )
  )

Use with apaTables

The package apaTables is very useful for getting something into the shape for APA and has the function to export individual tables into word. We can also shape statistical results with apaTables and then format that shape into an table with gt.

model <- lm(mpg ~ wt, mtcars)
summary(model)

## 
## Call:
## lm(formula = mpg ~ wt, data = mtcars)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -4.5432 -2.3647 -0.1252  1.4096  6.8727 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  37.2851     1.8776  19.858  < 2e-16 ***
## wt           -5.3445     0.5591  -9.559 1.29e-10 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 3.046 on 30 degrees of freedom
## Multiple R-squared:  0.7528, Adjusted R-squared:  0.7446 
## F-statistic: 91.38 on 1 and 30 DF,  p-value: 1.294e-10

model <- lm(mpg ~ wt, mtcars)
apaTables::apa.reg.table(model)

## 
## 
## Regression results using mpg as the criterion
##  
## 
##    Predictor       b       b_95%_CI  beta    beta_95%_CI sr2 sr2_95%_CI      r
##  (Intercept) 37.29** [33.45, 41.12]                                           
##           wt -5.34** [-6.49, -4.20] -0.87 [-1.05, -0.68] .75 [.56, .83] -.87**
##                                                                               
##                                                                               
##                                                                               
##              Fit
##                 
##                 
##      R2 = .753**
##  95% CI[.56,.83]
##                 
## 
## Note. A significant b-weight indicates the beta-weight and semi-partial correlation are also significant.
## b represents unstandardized regression weights. beta indicates the standardized regression weights. 
## sr2 represents the semi-partial correlation squared. r represents the zero-order correlation.
## Square brackets are used to enclose the lower and upper limits of a confidence interval.
## * indicates p < .05. ** indicates p < .01.
## 

model <- lm(mpg ~ wt, mtcars)
apaTables::apa.reg.table(model)[["table_body"]] %>%
  apa()

data(mtcars)
model <- lm(mpg ~ wt, mtcars)
apatable <- apaTables::apa.reg.table(model)

apa(apatable[["table_body"]], apatable[["table_title"]]) %>%
  tab_footnote(
    footnote = apatable[["table_note"]], 
    locations = cells_column_labels( 
      columns = vars(b))
  )