R/nice_mod.R

In rempsyc: Convenience Functions for Psychology

#' @title Easy moderations
#'
#' @description Easily compute moderation analyses, with effect
#' sizes, and format in publication-ready format.
#'
#' @inherit nice_lm details return
#'
#' @param data The data frame
#' @param response The dependent variable.
#' @param predictor The independent variable.
#' @param moderator The moderating variable.
#' @param moderator2 The second moderating variable, if applicable.
#' @param covariates The desired covariates in the model.
#' @param b.label What to rename the default "b" column (e.g.,
#' to capital B if using standardized data for it to be converted
#' to the Greek beta symbol in the [nice_table()] function). Now
#' attempts to automatically detect whether the variables were
#' standardized, and if so, sets `b.label = "B"` automatically.
#' Factor variables or dummy variables (only two numeric values)
#' are ignored when checking for standardization.
#' *This argument is now deprecated, please use argument
#' `standardize` directly instead.*
#' @param standardize Logical, whether to standardize the
#' data before fitting the model. If `TRUE`, automatically sets
#' `b.label = "B"`. Defaults to `TRUE`.
#' @param mod.id Logical. Whether to display the model number,
#' when there is more than one model.
#' @param ci.alternative Alternative for the confidence interval
#' of the sr2. It can be either "two.sided (the default in this
#' package), "greater", or "less".
#' @param ... Further arguments to be passed to the [lm()]
#' function for the models.
#'
#' @keywords moderation interaction regression
#' @export
#' @examplesIf requireNamespace("effectsize", quietly = TRUE)
#' # Make the basic table
#' nice_mod(
#'   data = mtcars,
#'   response = "mpg",
#'   predictor = "gear",
#'   moderator = "wt"
#' )
#'
#' # Multiple dependent variables at once
#' nice_mod(
#'   data = mtcars,
#'   response = c("mpg", "disp", "hp"),
#'   predictor = "gear",
#'   moderator = "wt"
#' )
#'
#' # Add covariates
#' nice_mod(
#'   data = mtcars,
#'   response = "mpg",
#'   predictor = "gear",
#'   moderator = "wt",
#'   covariates = c("am", "vs")
#' )
#'
#' # Three-way interaction
#' x <- nice_mod(
#'   data = mtcars,
#'   response = "mpg",
#'   predictor = "gear",
#'   moderator = "wt",
#'   moderator2 = "am"
#' )
#' x
#' @examplesIf requireNamespace("effectsize", quietly = TRUE) && packageVersion("effectsize") >= "0.8.3.5"
#' # Get interpretations
#' cbind(x, Interpretation = effectsize::interpret_r2_semipartial(x$sr2))
#'
#' @seealso
#' Checking simple slopes after testing for moderation:
#' \code{\link{nice_slopes}}, \code{\link{nice_lm}},
#' \code{\link{nice_lm_slopes}}. Tutorial:
#' \url{https://rempsyc.remi-theriault.com/articles/moderation}
#'

nice_mod <- function(data,
                     response,
                     predictor,
                     moderator,
                     moderator2 = NULL,
                     covariates = NULL,
                     b.label = "b",
                     standardize = TRUE,
                     mod.id = TRUE,
                     ci.alternative = "two.sided",
                     ...) {
  check_col_names(data, c(predictor, response, moderator, moderator2, covariates))
  rlang::check_installed("effectsize",
    version = get_dep_version("effectsize"),
    reason = "for this function."
  )

  if (!missing(b.label)) {
    message(paste(
      "The argument 'b.label' is deprecated.",
      "If your data is standardized, capital B will be used automatically.",
      "Else, please use argument 'standardize' directly instead."
    ))
  }

  data <- data %>%
    dplyr::select(dplyr::any_of(c(
      response,
      predictor,
      moderator,
      moderator2,
      covariates
    )))

  if (data_is_standardized(data)) {
    b.label <- "B"
  } else if (isTRUE(standardize)) {
    data <- lapply(data, scale)
    b.label <- "B"
  }

  if (!missing(covariates)) {
    covariates.term <- paste("+", covariates, collapse = " ")
  } else {
    covariates.term <- ""
  }
  if (!missing(moderator2)) {
    moderator2.term <- paste("*", moderator2, collapse = " ")
  } else {
    moderator2.term <- ""
  }
  formulas <- paste(
    response, "~", predictor, "*", moderator,
    moderator2.term, covariates.term
  )
  models.list <- lapply(formulas, stats::lm, data = data, ...)

  table.stats <- lapply(models.list, nice_lm, ci.alternative = ci.alternative)
  model.number.rows <- lapply(table.stats, nrow)
  table.stats <- dplyr::bind_rows(table.stats)

  if (length(models.list) > 1 && mod.id == TRUE) {
    model.number <- rep(seq_along(models.list), times = model.number.rows)
    table.stats <- stats::setNames(
      cbind(model.number, table.stats),
      c("Model Number", names(table.stats))
    )
  }
  names(table.stats)[names(table.stats) == "b"] <- b.label

  table.stats
}