R/get_age_equivalent.R
get_age_equivalent.Rd
This function calculates the ages at which a certain percent in the reference population passes the items.
get_age_equivalent( items, pct = c(10, 50, 90), key = "gsed", itembank = dscore::builtin_itembank, population = key, xunit = c("decimal", "days", "months") )
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 | A string that sets the key, the set of difficulty
estimates from a fitted Rasch model.
The built-in keys are: |
itembank | A |
population | A string describing the population. Currently
supported are |
xunit | A string specifying the unit in which age is measured
(either |
Tibble with four columns: item
, d
(D-score),
pct
(percentile), and a
(age-equivalent, in xunit
units).
#> # A tibble: 6 × 4 #> item d pct a #> <chr> <dbl> <dbl> <dbl> #> 1 ddicmm030 9.10 10 0.0415 #> 2 ddicmm030 11.3 50 0.0656 #> 3 ddicmm030 13.5 90 0.0913 #> 4 ddicmm050 67.3 10 2.35 #> 5 ddicmm050 69.5 50 2.60 #> 6 ddicmm050 71.7 90 NA