get_age_equivalent {dscore} | R Documentation |
Get age equivalents of items that have a difficulty estimate
Description
This function calculates the ages at which a certain percent in the reference population passes the items.
Usage
get_age_equivalent(
items,
pct = c(10, 50, 90),
key = NULL,
population = NULL,
transform = NULL,
itembank = dscore::builtin_itembank,
xunit = c("decimal", "days", "months"),
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 |
pct |
Numeric vector with requested percentiles (0-100). The
default is |
key |
String. Name of the key that bundles the difficulty estimates
pertaining one the same Rasch model. View |
population |
String. The name of the reference population to calculate DAZ.
Use |
transform |
Numeric vector, length 2, containing the intercept
and slope of the linear transform from the logit scale into the
the D-score scale. The default ( |
itembank |
A |
xunit |
A string specifying the unit in which age is measured
(either |
verbose |
Logical. Print settings. |
Value
data.frame
with four columns: item
, d
(D-score),
pct
(percentile), and a
(age-equivalent, in xunit
units).
Note
The function internally defines a scale factor given the key.
Examples
get_age_equivalent(c("gpagmc018", "gtogmd026", "ddicmm050"))