caa a22 4500 606242384 CHVBK 20210128101318.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s11336-014-9404-2 doi (NATIONALLICENCE)springer-10.1007/s11336-014-9404-2 On the Unidentifiability of the Fixed-Effects 3PL Model [Elektronische Daten] [Ernesto San Martín, Jorge González, Francis Tuerlinckx] The paper offers a general review of the basic concepts of both statistical model and parameter identification, and revisits the conceptual relationships between parameter identification and both parameter interpretability and properties of parameter estimates. All these issues are then exemplified for the 1PL, 2PL, and 1PL-G fixed-effects models. For the 3PL model, however, we provide a theorem proving that the item parameters are not identified, do not have an empirical interpretation and that it is not possible to obtain consistent and unbiased estimates of them. The Psychometric Society, 2014 consistent estimator nationallicence identified parameters nationallicence parameters of interest nationallicence statistical model nationallicence unbiased estimator nationallicence San Martín Ernesto Faculty of Mathematics, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul, Santiago, Chile aut González Jorge Faculty of Mathematics, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul, Santiago, Chile aut Tuerlinckx Francis Faculty of Psychology and Educational Sciences, KU Leuven, University of Leuven, Leuven, Belgium aut Psychometrika Springer US; http://www.springer-ny.com 80/2(2015-06-01), 450-467 0033-3123 80:2<450 2015 80 11336 https://doi.org/10.1007/s11336-014-9404-2 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11336-014-9404-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- San Martín Ernesto Faculty of Mathematics, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul, Santiago, Chile aut NATIONALLICENCE 700 1- González Jorge Faculty of Mathematics, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul, Santiago, Chile aut NATIONALLICENCE 700 1- Tuerlinckx Francis Faculty of Psychology and Educational Sciences, KU Leuven, University of Leuven, Leuven, Belgium aut NATIONALLICENCE 773 0- Psychometrika Springer US; http://www.springer-ny.com 80/2(2015-06-01), 450-467 0033-3123 80:2<450 2015 80 11336