Read item parameters from oplm PAR or CML files
path to a file in the (binary) OPLM PAR format or the human readable CML format
depends on the input. For .PAR files a data.frame with columns: item_id, item_score, beta, nbr, for .CML files also several statistics columns that are outputted by OPLM as part of the calibration.
It is very occasionally useful to calibrate new items on an existing scale. This function offers the possibility to read parameters from the proprietary oplm format so that they can be used to fix a new calibration in Dexter on an existing scale of items that were calibrated in oplm.