Averting the next credibility crisis in psychological science: Within-person methods for personalized diagnostics and intervention.

Abstract

Personalizing assessments, predictions, and treatments of individuals is currently a defining trend in psychological research and applied fields, including personalized learning, personalized medicine, and personalized advertisement. For instance, the recent pandemic has reminded parents and educators of how challenging yet crucial it is to get the right learning task to the right student at the right time. Increasingly, psychologists and social scientists are realizing that the between- person methods that we have long relied upon to describe, predict, and treat individuals may fail to live up to these tasks (e.g., Molenaar, 2004). Consequently, there is a risk of a credibility loss, possibly similar to the one seen during the replicability crisis (Ioannides, 2005), because we have only started to understand how many of the conclusions that we tend to draw based on between-person methods are based on a misunderstanding of what these methods can tell us and what they cannot. An imminent methodological revolution will likely lead to a change of even well-established psychological theories (Barbot et al., 2020). Fortunately, methodological solutions for personalized descriptions and predictions, such as many within-person analyses, are available and undergo rapid development, although they are not yet embraced in all areas of psychology, and some come with their own limitations. This article first discusses the extent of the theory-method gap, consisting of theories about within-person patterns being studied with between-person methods in psychology, and the potential loss of trust that might follow from this theory-method gap. Second, this article addresses advantages and limitations of available within- person methods. Third, this article discusses how within-person methods may help improving the individual descriptions and predictions that are needed in many applied fields that aim for tailored individual solutions, including personalized learning and personalized medicine.

Generalizability Crisis Meets Heterogeneity Revolution: Determining Under Which Boundary Conditions Findings Replicate and Generalize

“…When establishing the replicability, we typically compare sample-level coefficients and expect them to represent general laws (e.g., average treatment effects, or the one correlation coefficient for the sample). This follows the nomothetic rationale expecting all individuals to function according to one and the same law (e.g., Hamaker, 2012), which has been criticized as often unrealistic and of limited use (Beck & Jackson, 2020;Bolger et al, 2019;Bryan et al, 2021;Moeller, 2021;Molenaar, 2004;Richters, 2021). Richters (2021) argues that we neither know whether all individuals are affected by the same causal mechanisms, nor whether the path of causal transmission (direct versus mediated, bidirectional, etc.)…”

“…In particular, we apply Lakatos's proposition to examine not only whether but under what boundary conditions a theory is a useful description of the world, to the question whether and under which conditions a research finding is replicable and generalizable. Not only will that contribute to a more systematic understanding of and research on replicability and generalizability in longitudinal studies and beyond, but it will also be a contribution to what has been called the heterogeneity revolution (Bryan et al, 2021;Moeller, 2021).…”

Beyond main effects? Affect level as a moderator in the relation between affect dynamics and depressive symptoms

“…Based on our results, we can only draw conclusions regarding associations between affect dynamics and depressive symptoms on a between-person level, which does not inform us how affect dynamics and level interact within one person. Relations on a between-person versus within-person level can be vastly different (see Moeller, 2021 for a recent discussion). Thus, future intra-individual research is needed to examine the interaction between affect variability and affect level within individuals to examine whether higher variability at the intra-individual level could reduce depressive symptoms for individuals with high levels of NA and whether affect variability at the intraindividual level could trigger more depressive symptoms for individuals with low levels of NA.…”

“…This could also be interesting with regard to the seeming paradox that higher inertia and instability are negatively correlated with each other (i.e., individuals with instability show lower inertia), but both associate positively with depressive symptoms (Bos et al, 2019;Koval et al, 2013) 11 . It is possible that different individuals account for covariance of different between-person paths (Moeller, 2021). New statistical methods are on the way, such as latent class vector-autoregressive modeling, in which individuals with similar affective time-series patterns can be identified (Ernst et al, 2021).…”

Wachstumsverläufe der intrinsischen Wertüberzeugungen in Mathematik und Französisch: Zusammenhänge mit Berufsorientierungen

“…Beltz et al 2016). Dies hat den Vorteil, dass die intra-individuell identifizierten Verlaufsmuster über die Zeit sowie über die beiden Schulfächer hinweg stärker auf die dabei beschriebenen Individuen übertragbar sind, was bei Studien die rein inter-individuell basierte Ansätze verfolgen nicht gegeben sein muss (Moeller 2021). Damit bringt unsere Studie Hypothesen für verlaufsspezifische Interventionsstrategien in einer kritischen Phase der Adoleszenz auf, in der sich aufkeimende Zukunftspläne zu konkretisieren beginnen und zeigt, wie wichtig es ist, die Motivationsentwicklung von Schüler*innen intraindividuell (vgl.…”