Erratum to: On the Unidentifiability of the Fixed-Effects 3PL Model.

Condition 2 of Theorem 2 was incorrect in the published version. The correct condition 2 appears in this erratum. Theorem 2. Suppose that I ≥ 3 for the fixed-effects 3PL model. If ω1 = (α1, β1, c1) is fixed at(1, 0, 0), then1. The person parameters are identified by the observations.2. The item parameters (α2:J , β2:J , c2:J ) are not identified by the observations.