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The b parameter or the measure of the difficulty of the item. A histogram of the difficulty parameters is shown beside the difficulty estimates.
(Available only for 2PL and 3PL models.) The a parameter or the measure of the item discrimination. A histogram of the discrimination parameters is shown beside the discrimination estimates.
(Available only for 3PL models.) The c parameter or a measure of guessing.

Help created on 3/19/2020