Direct and Indirect Seasonal Adjustment Approaches: An Application for GDP Series

Year 2010, Volume: 7 Issue: 2, 25 - 44, 15.12.2010

Özlem Yiğit Bedriye Saraçoğlu

Abstract

The seasonal adjustment of aggregated time series can be obtained indirectly through the aggregation of the main components previously seasonally adjusted or directly seasonally adjusting the aggregated series. Unfortunately, these strategies could produce quite different results. In this paper we discussed the common criteria and diagnostics used to assess the quality of a seasonal adjustment and to compare seasonal adjustment results obtained with the alternative approaches known as direct or indirect in the literature. The direct and the indirect seasonal adjustment approaches are compared on the basis of the results obtained for the seasonal adjustment of the GDP series published by the Turkish Statistical Institute. In this study we have used the quarterly data pertaining to 1998:01–2009:02 period, and have concluded that the GDP is to be adjusted using the indirect approach.

Keywords

Direct and indirect aproach, Seasonal adjustment, Time series

Doğrudan ve Dolaylı Mevsim Düzeltme Yaklaşımları: GSYİH Serileri için Bir Uygulama

Abstract

Toplulaştırılmış zaman serilerinde mevsimsel düzeltme, mevsimsel düzeltilmiş ana grupların toplulaştırılması yoluyla dolaylı olarak ya da toplulaştırılmış serinin mevsimsellikten arındırılması yoluyla doğrudan elde edilebilir. Ne yazık ki bu stratejiler oldukça farklı sonuçlar üretebilir. Bu çalışmada literatürde doğrudan ve dolaylı yaklaşım olarak adlandırılan alternatif yaklaşımlarla elde edilmiş mevsimsel düzeltme sonuçlarını karşılaştırabilmek ve mevsimsel düzeltmenin kalitesini değerlendirebilmek için kullanılan genel ölçütler ve diyagnostikler tartışılmıştır. Doğrudan ve dolaylı yaklaşımla mevsimsel düzeltme yaklaşımları, Türkiye İstatistik Kurumu (TÜİK) tarafından yayımlanan Gayri Safi Yurtiçi Hasıla (GSYİH) serileriyle elde edilen mevsimsel düzeltme sonuçları temelinde karşılaştırılmıştır. 1998:01–2009:02 dönemine ait üç aylık verilerin kullanıldığı çalışmada GSYİH’nin dolaylı yaklaşımla mevsimsel düzeltilmesine karar verilmiştir.

Keywords

Doğrudan ve dolaylı yaklaşım, Mevsimsel düzeltme, Zaman serileri

References

• Bell, W. R., Hillmer, S. C., 1984. Issues Involved with the Seasonal Adjustment of Economic Time Series. Journal of Business & Economic Statistics, American Statistical Association, 2(4): 291-320.
• Burman, J. P., 1980. Seasonal Adjustment by Signal Extraction. Journal of the Royal Statistical Society A, 143:321-337.
• European Central Bank, 2000. Seasonal Adjustment of Monetary Aggregates and HICP for the Euro Area. http://www.ecb.int/pub/pdf/other/sama0008en.pdf, 21 Mayıs 2009.
• Dagum, E. B., 1979. On the Seasonal Adjustment of economic Time Series Aggregates: A Case Study of the Unemployment Rate, Counting the Labor Force, National Commion Employment and Unemployment Statistics. Appendix, 2:317-344.
• Dosse, J., Planas, C., 1996. Pre-adjustment in Seasonal Adjustment Methods: A Comparison of REGARIMA and TRAMO. Eurostat Working Group Document, No: D3/SA/07.
• Findley D. F., Soukup R. J., 2007. Detection And Modeling Of Trading Day Effects. U.S. Census Bureau Statistical Research Division, http://www.census.gov/ts/papers/ices00_td.pdf, 23 Aralık 2008.
• Fischer, B., 1995. Decomposition of Time Series - Comparing Different Methods in Theory and Practice. Eurostat Working Paper, No 9/1998/A/8.
• Ghysels, E., 1997. Seasonal adjustment and other data transformations. Journal of Business and Economic Statistics 15, 410-418.
• Ghysels, E., Osborn, D. R., 2001. The Econometric Analysis of Seasonal Time Series. Cambridge University Press, 978-0-521-56588-2.
• Gomez, V., Maravall, A., 1997. Program TRAMO and SEATS: Instructions for the User. Beta Version, (Online), Banco de Espana.
• Gomez, V., Maravall, A., 1998. Seasonal Adjustment and Signal Extraction in Economic Time Series. Banco de Espana, No 9809.
• Hood, C. C. H., Findley, D. F., 2001. Comparing Direct and Indirect Seasonal Adjustment of Aggregate Series. 2001 Proceedings of the American Statistical Association.
• Hylleberg, S., 2006. Seasonal Adjustment. University of Aarhus Department of Economics, Working Paper No. 2006-4.
• Kaiser, R., Maravall, A., 2000. Notes on Time Series Analysis, ARIMA Models and Signal Extraction. Banco de Espana, No 0012.
• Koçak, N. A., 2009. Takvim Etkileri: Ulusal Hesaplar Uygulaması. 17. İstatistik Araştırma Sempozyumu Bildiriler Kitabı, 2008, TÜİK, 154-168.
• Ladiray, D., Quenneville, B., 2001. Seasonal Adjustment with the X-11 Method. V: 158, Springer, New York, 9780387951713.
• Ladiray, D., Mazzi, G. L., 2003. Seasonal Adjustment of European Aggregates: Direct versus Indirect Approach. Proceedings of the Seminar on Seasonal Adjustment, Manna, M., Peronaci, R. Editors, European Central Bank, 37-66.
• Lothian, J., Morry, M., 1977. The Problem of Aggregation; Direct or Indirect. Working Paper, Time Series Research and Analysis Division, Statistics Canada, Ottawa ON, Canada.
• Maravall, A., 2005. Brief Description of the Programs. http://www.bde.es/webbde/es/secciones/servicio/software/tramo/summprogs.pdf.
• Maravall, A., 2006. An application of the TRAMO-SEATS automatic procedure; direct versus indirect adjustment. Computational Statistics & Data Analysis, Vol.50, No.9, 2167-2190.
• Maurin, L., 2003. Criteria to determine the optimal revision policy: A case study based on Euro zone monetary aggregates data. Proceedings of the Seminar on Seasonal Adjustment, Manna, M., Peronaci, R. editors, European Central Bank, 67-84.
• Otranto, E., Triacca, U., 2002. Measure to Evaluate the discreapancy Between Direct and Indirect Model-Based Seasonal Adjustment. Journal of Official Statistics, Vol 18, No 4, pp. 511-530.
• Peronaci, R., 2003. The Seasonal Adjustment of Euro Monetary Aggregates: Direct Versus Indirect Approach. Proceedings of the Seminar on Seasonal Adjustment, Manna, M., Peronaci, R. editors, European Central Bank, 91-108.
• Planas, C., 1997. Applied Time Series Analysis: Modeling, Forecasting, Unobserved Components Analysis and the Wiener-Kolmogorov Fitler. Eurostat Working Paper, No:66630002.
• Planas, C., Campolongo, F., 2000. The Seasonal Adjustment of Contemporaneously Aggregated Series. European Comission Working Paper, No:KS-AN-03-018-EN-N.
• Rietzler, K., Stephan, S., Wolters, J., 2000. Aggregation and Seasonal Adjustment Empirical Results for EMU Quarterly National Accounts. Discussion Papers of DIW Berlin from DIW Berlin, No 228, German Institute for Economic Research.