Original Article Evaluating the Construct Validity of Objective Personality Tests Using a Multitrait-Multimethod- Multioccasion-(MTMM-MO)- Approach Tobias Koch, 1 T. M. Ortner, 2 M. Eid, 1 J. Caspers, 1 and M. Schmitt 3 1 Department of Education and Psychology, Freie Universität Berlin, Germany, 2 Department of Psychology, Universität Salzburg, Austria, 3 Department of Psychology, Universität Koblenz-Landau, Germany Abstract. Although Objective Personality Tests (OPTs) have a long history in psychology and the field of psychological assessment, their validity, and reliability have not yet been sufficiently studied. In this study, we examined the convergent and discriminant validity of objective (personality) tests, Implicit Association Tests (IATs), and self-report measures for the assessment of conscientiousness and intelligence. Moreover, the convergent and discriminant validity of these measures was assessed on the trait (stable) and occasion specific (momentary) level by using the multimethod latent state-trait (MM-LST) model proposed by Courvoisier, Nussbeck, Eid, and Cole (2008) which allows for the decomposition of different sources of variance. Data from 367 students assessed on three different measurement occasions was incorporated. Results indicate generally low convergence of OPTs with data gained by other approaches. Additional analyses revealed that the OPTs used assess stable rather than momentary components of the constructs. Reliabilities of different tests ranged from .54 to .95. Furthermore, a substantial amount of trait method specificity revealed that different methods assess trait components that are not shared between OPTs and other measures. Data on the criterion validity of the objective conscientiousness test revealed that it is related to the punctuality of test takers in the laboratory. Keywords: OPT, Objective Test, Objective Personality Test, MTMM, intelligence, conscientiousness Objective personality tests (OPTs), defined as tests that deduce characteristics related to personality from observa- ble behavior in performance tasks or other highly standard- ized miniature situations (Cattell & Warburton, 1967), have a long history in psychological measurement. They can even be traced back to the assessment pioneer, James McKeen Cattell, and his 10 tests based on ‘‘experiment and measurement’’ in 1890. More recent, the history of OPTs is usually divided into two periods (see Ortner & Proyer, 2014): Starting in the 1940s, Raymond B. Cattell proposed to use so-called T-data for personality research. Within his theoretical framework, Cattell described objective (personality) tests as one of three sources of information within personality assessment besides self-report (Q-data) and biographic data (L-data; Cattell, 1946; Cattell & Kline, 1977). In line with this work, he created the first generation of OPTs, also known as Cursive Miniature Situations (Cattell, 1941, 1944) that stimulate behavioral expression of personality while fulfilling common standards of psychological tests. The proposed tests that also included standardized ability and achievement tests were characterized by a great varia- tion with respect to material and scoring methods (Cattell, 1968). During the last two decades, additional behavior-based methods of personality assessment, beyond self-report, have been developed, supported by the advances in computerized technologies. These tests, considered as the second generation of objective personality tests, have mostly benefitted from the development of computer tech- nologies that provide highly flexible methods of item pre- sentation and a precise registration of a person’s behavior (Ortner et al., 2007; Ortner & Proyer, 2014). Examples of this are the inclusion of tachistoscopically presented stimuli (Proyer, 2007; Proyer & Häusler, 2007), as well as the assessment of viewing times, reaction times (e.g., Proyer, 2007), reaction speed (Schmidt-Atzert, 2007), animated consequences of behavior (Lejuez et al., 2002), or other European Journal of Psychological Assessment 2014; Vol. 30(3):208–230 DOI: 10.1027/1015-5759/a000212 Ó 2014 Hogrefe Publishing