Probabilistic Targeted Factor Analysis
Miguel C. Herculano, Santiago Montoya-Blandón
TL;DR
Probabilistic Targeted Factor Analysis (PTFA) provides a likelihood-based framework for extracting latent factors that are explicitly targeted to economically meaningful outcomes. By modeling $\mathbf{x}=\mathbf{P}\mathbf{f}+\mathbf{e}_x$ and $\mathbf{y}=\mathbf{Q}\mathbf{f}+\mathbf{e}_y$ with $\mathbf{f}\sim\mathcal{N}(\mathbf{0},\mathbf{V}_F)$, PTFA yields a Gaussian posterior $\mathbf{f}|\mathbf{x},\mathbf{y}$ and employs a fast EM algorithm to estimate the loadings and noise variances, enabling uncertainty quantification. The framework naturally extends to incomplete data, mixed-frequency sampling, stochastic volatility, and dynamic factor behavior, and it is demonstrated to improve the recovery and forecasting of targeted factors in simulations and three economic/financial applications: targeted financial conditions indices, macroeconomic forecasting, and equity premium prediction. Simulation results and empirical exercises show PTFA outperforms traditional PLS and PCA approaches, particularly under high noise or missing data, and the method comes with an open-source implementation to facilitate adoption. The probabilistic formulation also opens avenues for Bayesian or variational extensions and richer prior structures while maintaining computational efficiency.
Abstract
We develop Probabilistic Targeted Factor Analysis (PTFA), a likelihood-based framework for constructing latent factors that are explicitly targeted to variables of economic interest. PTFA provides a probabilistic foundation for Partial Least Squares, allowing supervised factor extraction under uncertainty. The model is estimated via a fast expectation maximization algorithm and naturally accommodates missing data, mixed-frequency observations, stochastic volatility, and factor dynamics. Simulation evidence shows that PTFA improves recovery of economically relevant latent factors relative to standard PLS, particularly in noisy environments. Applications to financial conditions indices, macroeconomic forecasting, and equity premium prediction illustrate the measurement and forecasting gains delivered by targeted probabilistic factor extraction.
