Calculates the next item to administer in an adaptive test to measure the D-score. Uses the previously administered items and item scores as input.

Calculates the next item to administer in an adaptive test to measure the D-score. Uses the previously administered items and item scores as input.

Usage

dcat_next(
  txt = "",
  instrument = "gs1",
  key = "gsed2510",
  p = 50,
  session = "",
  format = "3.1",
  ...
)

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.

instrument

A character vector with 3-position codes of instruments that should match. The default is instrument = "gs1" for GSED SF; instrument = NULL allows for all instruments.

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 key = "gsed2510".

p

percentage to pass the item, difficulty in percentile units.

session

Optional session key if data is already uploaded to sitehost.

format

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

...

Ignored

Value

A string of milestones

Author

Iris Eekhout 2025

Examples

txt <- system.file("examples", "example_v3.1.json", package = "bdsreader")
dcat_next(txt = txt, p = 50)
#> [1] "gs1lgc110"