nret.translator: Convert NRET/ET data between klausuR and other software
In klausuR: Multiple Choice Test Evaluation

nret.translator

R Documentation

Convert NRET/ET data between klausuR and other software

Description

This function should help to interchange answer data between R and other statistical software packages – especially SPSS, but it's probably useful for other products as well.

Usage

nret.translator(
  dat,
  items = NULL,
  spss = "out",
  corr = FALSE,
  num.alt = NULL,
  klausuR.alt = c(is.true = "+", is.false = "-", missing = "0", err = "*"),
  spss.alt = c(is.true = "2", is.false = "1", missing = "0", err = "3"),
  rm.old.vars = TRUE,
  items.only = FALSE,
  klausuR.prefix = c(),
  spss.prefix = c()
)

Arguments

`dat`	A data.frame, the object to convert.
`items`	Optional vector defining the columns to convert. If `NULL`, the function will try to autodetect Items: `klausuR` type items are expected to be named `"ItemXXX"`, with XXX indicating the item number, SPSS type items `"itemXXXaYY"`, with XXX indicating the item number and YY the number of the answer alternative.
`spss`	Either "in" or "out", depending on the direction of conversion.
`corr`	Logical. Set to `TRUE` if `dat` is a vector with the correct answers. If `corr=TRUE` and `spss="in"`, you must also set `num.alt` accordingly!
`num.alt`	A numeric value definig the number of answer alternatives for each item. Can be a vector, if items have different numbers of options. If it is shorter than the number of items, it will be repeated for all items.
`klausuR.alt`	A named vector defining the codes for `klausuR` type of answers.
`spss.alt`	A named vector defining the codes for SPSS type of answers.
`rm.old.vars`	Logical. If `TRUE`, the converted columns will not be returned. Only relevant if `corr=FALSE`.
`items.only`	Logical. If `TRUE`, only the converted columns will be returned. Only relevant if `corr=FALSE`.
`klausuR.prefix`	A named character vector with two optional elements, `item` and `corr`, defining the name prefix used for the items in the test data and the vector with correct answers, respectively. Defaults to `item="Item"` and `corr="Item"`.
`spss.prefix`	Like `klausuR.prefix`, but for the SPSS data. Defaults to `item="item"` and `corr="corr"`.

Details

klausur expects data in a special format if it should be evaluated according to (Number Right) Elimination Testing (NRET/ET), only one variable per item. Other software products might not be able to process this rather condensed format. In that case, you will most likely need several variables for each item, i.e. one per answer alternative. Adding to that, the coding of answers is by default done with "+", "-", "0" and "*" in klausuR, again a solution that might confuse other products.

This function translates data in both directions, and does also convert vectors giving the correct answer. The latter will turn a klausuR type answer string into a number indicating the correct alternative (and the other way round). This means that it will only work if there's exactly one valid answer to each item. If you convert towards SPSS, the resulting list will also include SPSS syntax to define variables respectively.

Value

If corr=FALSE, a data.frame with more or less columns (depending on rm.old.vars and items.only). If corr=TRUE, returns a named vector if spss="in" and a list if spss="out" (containing SPSS syntax in the element syntax and also a named vector, called answ).

Note

The conversion is done on an object basis, that is, nret.translator will not open or write files, but take and return R objects. The function should ignore any other columns/variables in the object.

Author(s)

m.eik michalke meik.michalke@uni-duesseldorf.de

Examples

## Not run: 
# from SPSS to R
data(spss.data)
klausuR.data <- nret.translator(spss.data, spss="in")
spss.corr <- c(
   item01=2, item02=3, item03=3, item04=3, item05=2,
   item06=2, item07=3, item08=1, item09=1, item10=2)
klausuR.corr <- nret.translator(spss.corr, spss="in", corr=TRUE, num.alt=3)

# from R to SPSS
spss.data <- nret.translator(klausuR.data)
spss.corr <- nret.translator(klausuR.corr, corr=TRUE, num.alt=3)
# if you find the syntax useful
cat(spss.corr$syntax, file="~/somewhere/NRET.sps")

## End(Not run)

klausuR documentation built on April 5, 2022, 1:15 a.m.