Routine Psychological Testing of the Individual Is Not Valid

Abstract

In this article, we present and argue our assertion that current routine psychological testing of individuals is not valid. To support our assertion, we review the concept of ergodicity, Birkhoff's theorem, and Molenaar's manifesto, which together support our contention that the direct transposition of population estimations for producing inferences about the individual is not valid. We argue that this practice of direct transposition is the root cause of why routine psychological testing of individual is not valid. We then provide an example of a common application of psychological testing of an individual, explaining why this practice is not valid. Finally, we discuss how the intraindividual (or within-person) approach provides some prospect for valid individual testing and also introduces new challenges. We hope that our questioning of current psychological testing practices motivates researchers to propose and study novel methodological propositions to address the issues raised by our assertion.

Proposing an Achievement Simulation Methodology to Allow the Estimation of Individual in Clinical Testing Context

“…In this paper we claimed that, if the clinician wants to produce a correct inference about the individual (FISHER, 2018;GOMES et al, 2018;MOLENAAR, 2004MOLENAAR, , 2007, it is mandatory that she or he estimates the individual. We also stated that the usual methods for estimating the individual demand a huge number of testing occasions, which led us to claim that the clinics of the individual is, nowadays, an almost impossible task.…”

“…This condition causes serious implications in clinical testing contexts, leading Gomes et al (2018), through a detailed presentation of the ergodic theorems, to conclude that the routine psychological testing of the individual is not valid. According to Gomes et al (2018), performing a valid psychological testing of the individual implies that the individual parameters must be estimated, which means applying the same test a great number of occasions. Repeating many times the application of a test involving the respondents' performance is a procedure which is rarely attainable, e.g.…”

A Primer on Practical Significance

“…Policymakers 2 Certain effect size estimates, such as correlation and other statistical measures that use this as the basis, such as factor structurewhen derived from a cross-sectional sample cannot be assured to have same values for longitudinal samples (Molenaar, 2009). This lack of group-to-individual generalizability feature heavily on within human processes such as personality, intelligence, cognitive processes, and mental disorders; so estimating these from cross-sectional samples are said to have potentially misleading estimates and interpretation (Borsboom, Kievit, Cervone, & Hood, 2009;Gomes, de Araujo, do Nascimento, & Jelihovschi, 2018) However, this is not the case for experimental studies, in which the average treatment effect is typically the best guess for any particular individual's treatment effect (Gerber and Green, 2012). How or other stakeholders?…”

The reasons why the Regression Tree Method is more suitable than General Linear Model to analyze complex educational datasets

“…For example, factor analysis (Gomes, Linhares et al, 2021;Matos et al, 2019) and item response theory (Golino et al, 2015; assume that scientific constructs are latent variables that explain the variance of observable variables, which are, in general, respondents' performance in tasks (Gomes & Nascimento, 2021;Gomes et al, 2021aGomes et al, , 2021bGomes et al, , 2021c or respondents' self-reports about certain statements, words, and so on (Fleith & Gomes, 2019;. When factor analysis or item response theory estimate latent variables in an individual, the time parameter is added, usually assuming that the previous response has an influence over the individual's response (Ferreira & Gomes, 2017;Gomes et al, 2018;Rodrigues & Gomes, 2020). These rules constrain the evidence that can be constructed by the researcher.…”