Paper #1711

Title:

Forecasting in the presence of instabilities: How do we know whether models predict well and how to improve them

Author:

Barbara Rossi

Date:

November 2019 (Revised: July 2021)

Abstract:

This article provides guidance on how to evaluate and improve the forecasting ability of models in the presence of instabilities, which are widespread in economic time series. Empirically relevant examples include predicting the financial crisis of 2007-2008, as well as, more broadly, fluctuations in asset prices, exchange rates, output growth and inflation. In the context of unstable environments, I discuss how to assess models forecasting ability; how to robustify models' estimation; and how to correctly report measures of forecast uncertainty. Importantly, and perhaps surprisingly, breaks in models' parameters are neither necessary nor sufficient to generate time variation in models' forecasting performance: thus, one should not test for breaks in models'parameters, but rather evaluate their forecasting ability in a robust way. In addition, local measures of models' forecasting performance are more appropriate than traditional, average measures.

Keywords:

forecasting, instabilities, time variation, inflation, structural breaks, density forecasts, great recession, forecast confidence intervals, output growth, business cycles

JEL codes:

E4, E52, E21, H31, I3, D1

Area of Research:

Statistics, Econometrics and Quantitative Methods

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