Estimation of linear non-Gaussian acyclic models for latent factors

Many methods have been proposed for discovery of causal relations among observed variables. But one often wants to discover causal relations among latent factors rather than observed variables. Some methods have been proposed to estimate linear acyclic models for latent factors that are measured by observed variables. However, most of the methods use data covariance structure alone for model identification, and this leads to a number of indistinguishable models. In this paper, we show that a linear acyclic model for latent factors is identifiable when the data are non-Gaussian.