Recode clinical instrument responses to consecutive Rasch categories

Turns a persons x items table of responses on an instrument's native scale (e.g. the weighted Barthel levels 0/5/10/15) into the consecutive integer categories 0..m that a Rasch model expects, using the instrument's declared admissible item_values as the category order.

Usage

raschRecode(instrument, responses)

Arguments

instrument

A ClinicalInstrument or an instrument id.

responses

A persons x items matrix or data.frame; columns are matched to the instrument's items by name, or taken in the instrument's item order if unnamed.

Value

An integer matrix of consecutive category codes (0..m per item), with the instrument's item names as columns.

See also

raschAnalyze()

Examples

resp <- rbind(c(10, 5, 5, 10, 10, 10, 10, 15, 15, 10),
              c(5, 0, 0, 5, 5, 5, 5, 10, 5, 0))
colnames(resp) <- getInstrument("barthel")@items
raschRecode("barthel", resp)
#>      feeding bathing grooming dressing bowels bladder toilet_use transfers
#> [1,]       2       1        1        2      2       2          2         3
#> [2,]       1       0        0        1      1       1          1         2
#>      mobility stairs
#> [1,]        3      2
#> [2,]        1      0