By: |
Tae-Hwy Lee (Department of Economics, University of California Riverside);
Ekaterina Seregina (Colby College) |
Abstract: |
In this paper we develop a novel method of combining many forecasts based on
a machine learning algorithm called Graphical LASSO (GL). We visualize
forecast errors from different forecasters as a network of interacting
entities and generalize network inference in the presence of common factor
structure and structural breaks. First, we note that forecasters often use
common information and hence make common mistakes, Â which makes the forecast
errors exhibit common factor structures. We use the Factor Graphical LASSO
(FGL, Lee and Seregina (2023)) to separate common forecast errors from the
idiosyncratic errors and exploit sparsity of the precision matrix of the
latter. Second, since the network of experts changes over time as a response
to unstable environments such as recessions, it is unreasonable to assume
constant forecast combination weights. Hence, we propose Regime-Dependent
Factor Graphical LASSO (RD-FGL)Â that allows factor loadings and idiosyncratic
precision matrix to be regime-dependent. We develop its scalable
implementation using the Alternating Direction Method of Multipliers (ADMM)
to estimate regime-dependent forecast combination weights. The empirical
application to forecasting macroeconomic series using the data of the
European Central Bank’s Survey of Professional Forecasters (ECB SPF)
demonstrates superior performance of a combined forecast using FGL and RD-FGL. |
Keywords: |
Common Forecast Errors, Regime Dependent Forecast Combination, Sparse Precision Matrix of Idiosyncratic Errors, Structural Breaks. |
JEL: |
C13 C38 C55 |
Date: |
2023–09 |
URL: |
http://d.repec.org/n?u=RePEc:ucr:wpaper:202310&r=for |