Winsteps reports student raw scores in perfect alignment with student abilities, Table 17.1. But it reports item difficulties in a fuzzy array, Table 13.1. A range of item difficulty raw score counts can yield the same measure. Two difficult items can be worth the same as three easy items in measures.
I have learned, in the last 12 months, that there is a difference between counting things and measuring them. Counting is measuring only if all items being counted have the exact same properties. This brings my audit of the Rasch model to a close. In the process, Winsteps has become a friend that adds finer detail to Power Up Plus (PUP) when using the Partial Credit Rasch Model.