Fig. 1

Measurement models with reflective (a) and formative (b) indicators. Note: a The latent variable η determines the score of the four items y₁ to y₄, all of which are measurements of the same construct. The item-level errors are depicted by ε’s, and the factor loadings are depicted by λ’s. The mean structure refers to the expected value of the observed variables. b The latent variable η is determined by the scores of items x₁ to x₄, each of which is a measurement of a different aspect of the latent construct. The weights on the construct are depicted by γ’s, and the error term of the construct is ζ. In the formative model, the intercept α captures the mean structure of the model. In both figures, the square boxes represent observed variables, whereas the ovals represent unobserved (latent) variables, which were estimated on the basis of the items