Sunday, September 24, 2017

Egalitarian LASSO for Forecast Combination

Here's a new one.  It was something of a long and winding road.  We introduce simple "egalitarian LASSO" procedures that set some combining weights to zero and shrink those remaining toward equality.  The feasible versions don't work very well, due do difficulties associated with cross-validating tuning parameters in small samples, but the lessons learned in studying the infeasible version turn out to be very valuable -- indeed they directly motivate a new procedure, which we call "best <N-averaging", which solves the cross-validation problem and performs intriguingly well.

Diebold, F.X. and Shin, M. (2017), “Beating the Simple Average:  Egalitarian LASSO for Combining Economic Forecasts”, Penn Institute for Economic Research (PIER) Working Paper No. 17-017, available at SSRN: https://ssrn.com/abstract=3032492.