title: Erratum to: On the Unidentifiability of the Fixed-Effects 3PL Model.
abstract: 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.
authors.affiliation: Faculty of Mathematics, Pontificia Universidad Católica de Chile, Measurement Center Mide UC, Ceppe-UC and Université Catholique de Louvain, Vicuña Mackenna, 4860 , Macul, Santiago, Chile. esanmart@mat.puc.cl.
authors.forename: Ernesto
authors.initials: E
authors.lastname: San Martín
authors.affiliation: Pontificia Universidad Católica de Chile and Measurement Center Mide UC, Macul, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: González
authors.affiliation: University Of Leuven, Leuven, Belgium.
authors.forename: Francis
authors.initials: F
authors.lastname: Tuerlinckx