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Calculates the domain specific D-score and DAZ for each visit

Source: R/calculate_ddomain.R
calculate_ddomain.Rd

The function calculate_ddomain() calculates five domain scores for the D-score. Note that the domain scores may be highly variable due to the small number of items per domain.

Usage

calculate_ddomain(
  txt = "",
  session = "",
  format = "3.1",
  append = c("ddi", "gs1"),
  key = NULL,
  population = NULL,
  set = "GFCLS",
  domain = NULL,
  loc = "",
  ...
)

Arguments

txt

A JSON string, URL, or file with BDS data in JSON format. Data should conform to the BDS JGZ 3.2.5 specification.

session

Optional session key if data is already uploaded to sitehost.

format

JSON schema version, e.g., "3.0". Used when uploading.

append

Optional vector of strings indicating which instrument to base D-score calculations on. Currently supports ddi and gs1. Requires JSON schema V3.0 or later.

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 = "gsed2510". View builtin_keys for an overview of the available keys.

population

String. The name of the reference population to calculate DAZ. Use with(builtin_references, table(key, population)) to see which built-in references are available for key - population combinations. If not specified, the function set the default population as builtin_keys$base_population[key == builtin_keys$key].

set

String. The name of the set of domains to use. See with(builtin_domaintable, table(set, domain)) for the domain names in each set.

domain

character vector of the name of the domain(s) for which to compute the domain score. Per default all domains in the set are used .

loc

Deprecated. Use session instead.

...

Ignored

Value

A list of data.frames.

Author

Iris Eekhout 2025

Examples

fn <- system.file("testdata", "Laura_S.json", package = "james")
df <- calculate_dscore(txt = fn)
head(df, 4)
#> [1] a   n   p   d   sem daz
#> <0 rows> (or 0-length row.names)