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Evaluating the forecast quality of GDP components: An application to G7


  • Paulo Júlio

    () (Office for Strategy and Studies, Portuguese Ministry of Economy and Employment)

  • Pedro M. Esperança



We evaluate the quality of OECD's and IMF's forecasts for real GDP growth and for GDP expenditure components. We use a scaled statistic to compare the prediction models' performance across GDP components with different volatilities and decompose the GDP forecast error into the corresponding component contributions. Moreover, we use two recently proposed statistics - Mean of Total Weighted Absolute Error and Mean of Total Weighted Squared Error - to evaluate the overall accuracy of component predictions. We conclude that overpredictions in investment and net exports explain GDP overpredictions at 1-year horizons. Accurate GDP forecasts for same-year predictions are mostly explained by canceling out effects in component prediction errors - mainly in exports and imports - rather than by accurate component predictions. We also show that forecasts are in general inefficient for both GDP and its components and that the 2008 crisis had a large negative effect on the quality of forecasts being issued, but not on the predictive quality of forecast models.

Suggested Citation

  • Paulo Júlio & Pedro M. Esperança, 2012. "Evaluating the forecast quality of GDP components: An application to G7," GEE Papers 0047, Gabinete de Estratégia e Estudos, Ministério da Economia, revised Apr 2012.
  • Handle: RePEc:mde:wpaper:0047

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    References listed on IDEAS

    1. Victor Zarnowitz & Phillip Braun, 1993. "Twenty-two Years of the NBER-ASA Quarterly Economic Outlook Surveys: Aspects and Comparisons of Forecasting Performance," NBER Chapters,in: Business Cycles, Indicators and Forecasting, pages 11-94 National Bureau of Economic Research, Inc.
    2. Oller, Lars-Erik & Barot, Bharat, 2000. "The accuracy of European growth and inflation forecasts," International Journal of Forecasting, Elsevier, vol. 16(3), pages 293-315.
    3. Frederick L. Joutz, 1988. "Informational efficiency tests of quarterly macroeconometric GNP forecasts from 1976 to 1985," Managerial and Decision Economics, John Wiley & Sons, Ltd., vol. 9(4), pages 311-330, December.
    4. Keane, Michael P & Runkle, David E, 1990. "Testing the Rationality of Price Forecasts: New Evidence from Panel Data," American Economic Review, American Economic Association, vol. 80(4), pages 714-735, September.
    5. Hyndman, Rob J. & Koehler, Anne B., 2006. "Another look at measures of forecast accuracy," International Journal of Forecasting, Elsevier, vol. 22(4), pages 679-688.
    6. Loungani, Prakash, 2001. "How accurate are private sector forecasts? Cross-country evidence from consensus forecasts of output growth," International Journal of Forecasting, Elsevier, vol. 17(3), pages 419-432.
    7. Ash, J. C. K. & Smyth, D. J. & Heravi, S. M., 1998. "Are OECD forecasts rational and useful?: a directional analysis," International Journal of Forecasting, Elsevier, vol. 14(3), pages 381-391, September.
    8. Vuchelen, Jef & Gutierrez, Maria-Isabel, 2005. "A direct test of the information content of the OECD growth forecasts," International Journal of Forecasting, Elsevier, vol. 21(1), pages 103-117.
    9. Joutz, Fred & Stekler, H. O., 2000. "An evaluation of the predictions of the Federal Reserve," International Journal of Forecasting, Elsevier, vol. 16(1), pages 17-38.
    10. Paulo Júlio & Pedro M. Esperança & João C. Fonseca, 2011. "Evaluating the forecast quality of GDP components," GEE Papers 0041 Classification-C52, , Gabinete de Estratégia e Estudos, Ministério da Economia, revised Oct 2011.
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    More about this item


    Forecast evaluation; GDP expenditure components; Mean of total weighted absolute error; Mean of total weighted squared error; G7; 2008 crisis;

    JEL classification:

    • C52 - Mathematical and Quantitative Methods - - Econometric Modeling - - - Model Evaluation, Validation, and Selection
    • C53 - Mathematical and Quantitative Methods - - Econometric Modeling - - - Forecasting and Prediction Models; Simulation Methods
    • E37 - Macroeconomics and Monetary Economics - - Prices, Business Fluctuations, and Cycles - - - Forecasting and Simulation: Models and Applications

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