get_tau: Obtain difficulty parameters from item bank

In D-score/dscore: D-Score for Child Development

Obtain difficulty parameters from item bank

Description

Searches the item bank for matching items, and returns the difficulty estimates. Matching is done by item name. Comparisons are done in lower case.

Usage

get_tau(
  items,
  key = NULL,
  itembank = dscore::builtin_itembank,
  verbose = FALSE
)

Arguments

items	A character vector containing names of items to be included into the D-score calculation. Milestone scores are coded numerically as 1 (pass) and 0 (fail). By default, D-score calculation is done on all items found in the data that have a difficulty parameter under the specified key.
key	String. They key identifies 1) the difficulty estimates pertaining to a particular Rasch model, and 2) the prior mean and standard deviation of the prior distribution for calculating the D-score. The default key NULL sets key = "gsed2406". View builtin_keys for an overview of the available keys.
itembank	A data.frame with at least three columns named key, item and tau. By default, the function uses dscore::builtin_itembank. If you specify your own itembank, then you should also provide the relevant transform and qp arguments.
verbose	Logical. Print settings.

Value

A named vector with the difficulty estimate per item with length(items) elements.

Author(s)

Stef van Buuren 2020

See Also

builtin_itembank(), dscore()

Examples

# difficulty levels in the GHAP lexicon
get_tau(items = c("ddifmd001", "DDigmd052", "xyz"))

D-score/dscore documentation built on June 29, 2024, 6:25 p.m.