[Rasch] Concurrent calibration in Rasch and person parameter estimation
mike at winsteps.com
Tue Dec 31 10:50:51 AEDT 2019
thank you for your questions.
> I have two datasets on the same group. The sample size is 79, the
number of items was 40 and 55 respectively. I have 3 questions.
> Q1: how do we do concurrent calibration in Rasch?
Reply: This depends on what you want to discover. Simplest is to "rack"
the two datasets, so that there are 79 persons and 95 items. Put a code
in each item label so that you can do a Differential Person Function
(DPF) analysis of person-by-dataset. (or transpose the data and do a DIF
> Q2: what are some other ways to estimate person parameters apart
from the use of item responses?
Reply: Do you have other information about the persons, such as School
Grade, Age, Health, Occupation, Income? These may give a rough estimate
of person ability.
> Q3: Can TAM (the R package) do Q1 and Q2? If not, what programs
Reply: TAM can do Q1, not Q2.
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