abbreviate_scale: Abbreviate a scale

In Deleetdk/kirkegaard: kirkegaard

Abbreviate a scale

Description

This function abbreviates a scale by iteratively adding or removing items that are the least useful for predicting a criterion variable. The function can use a max loading, backwards, forwards, or genetic algorithm method to select items.

Usage

abbreviate_scale(
  items,
  criterion_vars = NULL,
  item_target,
  method = "forwards",
  selection_method = "rc",
  mirt_args = NULL,
  save_fits = T,
  seed = 1,
  max_generations = 100,
  population_size = 100,
  mutation_rate = 0.1,
  selection_ratio = 0.2,
  stop_search_after_generations = 10,
  include_parents = T,
  difficulty_balance_groups = NULL,
  residualize_loadings = F,
  reliability_at = "total"
)

Arguments

items	A data frame or matrix of items
criterion_vars	A data frame of criterion variables
item_target	The number of items to retain
method	The method to use for item selection. Options are "backwards", "forwards", "max_loading", or "genetic".
selection_method	The method to use for selecting items. Options are "rc" (average of correlation with criterion variable(s) and reliability), "r" (reliability), or "c" (correlation with criterion variable(s)).
mirt_args	A list of arguments to pass to the mirt function
save_fits	Whether to save the fits and scores for each item set. This might be useful for further analysis, but it also takes up memory.
seed	A seed to use for reproducibility. Default is 1.
max_generations	The maximum number of generations to use for the genetic algorithm. Default is 100.
population_size	The size of the population to use for the genetic algorithm. Default is 100.
mutation_rate	The mutation rate to use for the genetic algorithm. Default is 0.1.
selection_ratio	The ratio of the population to select for the next generation. Default is 0.20.
stop_search_after_generations	The number of generations to wait for no improvement before stopping the search. Default is 10.
include_parents	Whether to include the parents in the next generation. Default is TRUE.
difficulty_balance_groups	The number of groups to balance difficulty across. Default is NULL.
residualize_loadings	Whether to residualize loadings based on difficulty for selection purposes. Default is FALSE.

Value

A list of results. You probably want to call GG_scale_abbreviation() on these.

Examples

library(mirt)
#simulate some mirt data 2PL
set.seed(1)
dat = mirt::simdata(N = 1e3, itemtype = "2PL", a = runif(100, 0.5, 2), d = rnorm(100, sd = 0.5))
#fit the model
fit = mirt::mirt(dat, 1)
#scale abbreviation
short_scale = abbreviate_scale(as.data.frame(dat), method = "max_loading", item_target = 10)
#plot
GG_scale_abbreviation(short_scale)

Deleetdk/kirkegaard documentation built on May 8, 2024, 12:27 a.m.