The theoretical status of latent variables.

TLDR

The article reviews the theoretical status of latent variables in modern test theory, emphasizing their relationship with indicators. It argues that a realist ontology and explicit individual‑level processes are required to consistently interpret latent variable models and link intraindividual causal conclusions to interindividual differences. The authors discuss research strategies and propose a typology of constructs to incorporate individual‑level processes into measurement models. They conclude that the latent variable–indicator relation can be causal, yet it does not apply at the individual level in interindividual difference measurement models.

Abstract

This article examines the theoretical status of latent variables as used in modern test theory models. First, it is argued that a consistent interpretation of such models requires a realist ontology for latent variables. Second, the relation between latent variables and their indicators is discussed. It is maintained that this relation can be interpreted as a causal one but that in measurement models for interindividual differences the relation does not apply to the level of the individual person. To substantiate intraindividual causal conclusions, one must explicitly represent individual level processes in the measurement model. Several research strategies that may be useful in this respect are discussed, and a typology of constructs is proposed on the basis of this analysis. The need to link individual processes to latent variable models for interindividual differences is emphasized.