How to display coefficients in scientific notation with stargazer

Question

I want to compare the results of different models (lm, glm, plm, pglm) in a table in R using stargazer or a similar tool. However I can't find a way to display the coefficients in scientific notation. This is kind of a problem because the intercept is rather large (about a million) while other coefficients are small (about e-7) which results in lots of useless zeros making it harder to read the table.

I found a similar question here: Format model display in texreg or stargazer R as scientific. But the results there require rescaling the variables and since I use count data I wouldn't want to rescale it.

I am grateful for any suggestions.

Answer 1

Another robust way to get scientific notation using stargazer is to hack the digit.separator parameter. This option allows the user to specify the character that separates decimals (usually a period . in most locales). We can usurp this parameter to insert a uniquely identifiable string into any number that we want to be able to find using regex. The advantage of searching for numbers this way is that we shall only find numbers that correspond to numeric values in the stargazer output. I.e. there is no possibility to also match numbers that are part of variable names (e.g. X_12345) or that are part of the latex formatting code (e.g. \hline \\[-1.8ex]). In the following I use the string ::::, but any unique character string (such as a hash) that we will not find elsewhere in the table will do. It's probably best to avoid having any special regex characters in the identifier mark, as this will complicate things slightly.

Using the example model m1 from this other answer.

mark  = '::::'
star = stargazer(m1, header = F, decimal.mark  = mark, digit.separator = '')

replace_numbers = function(x, low=0.01, high=1e3, digits = 3, scipen=-7, ...) {
  x = gsub(mark,'.',x)
  x.num = as.numeric(x)
  ifelse(
    (x.num >= low) & (x.num < high), 
    round(x.num, digits = digits), 
    prettyNum(x.num, digits=digits, scientific = scipen, ...)
  )
}    

reg = paste0("([0-9.\\-]+", mark, "[0-9.\\-]+)")
cat(gsubfn(reg, ~replace_numbers(x), star), sep='\n')

Update If you want to ensure that trailing zeros are retained in the scientific notation, then we can use sprintf instead of prettyNum.

Like this

replace_numbers = function(x, low=0.01, high=1e3, digits = 3) {
  x = gsub(mark,'.',x)
  x.num = as.numeric(x)
  form = paste0('%.', digits, 'e')
  ifelse(
    (abs(x.num) >= low) & (abs(x.num) < high), 
    round(x.num, digits = digits), 
    sprintf(form, x.num) 
  )
}