Forecast combination through dimension reduction techniques

This paper considers several methods of producing a single forecast from several individual ones. We compare ‘standard’ but hard to beat combination schemes (such as the average of forecasts at each period, or consensus forecast and OLS‐based combination schemes) with more sophisticated alternatives that involve dimension reduction techniques. Specifically, we consider principal components, dynamic factor models, partial least squares and sliced inverse regression. Our source of forecasts is the Survey of Professional Forecasters, which provides forecasts for the main US macroeconomic aggregates. The forecasting results show that partial least squares, principal component regression and factor analysis have similar performances (better than the usual benchmark models), but sliced inverse regression shows an extreme behavior (performs either very well or very poorly).