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Modeling Domestic Price Volatility for Cereal Crops in Ethiopia

Received: 28 March 2021    Accepted: 2 November 2021    Published: 12 November 2021
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Abstract

The volatility in the domestic prices of maize and teff crops has been found to vary over time from month to month. Thus, Families of time series models namely, ARCH with their extensions to generalized ARCH, GARCH and EGARCH models with ARIMA mean equations were considered to the data. The best fitting model among each family of models was selected based on how well the model captures the variations in the data. The optimal lag specification for the models are accessed via AIC and SBIC. Comparisons of the symmetric and asymmetric selected models were carried out based on the significance of asymmetric term in the EGARCH model. Thus, statistically significance of asymmetric term and least forecast error from the model established that the EGARCH model with GED for residuals was superior to the GARCH model. Therefore, the ARIMA(2,0,3)-EGARCH(1,1) and ARIMA(0,0,3)-EGARCH(2,3) were chosen to be the best fitting models among the ARIMA(p, d, q)-GARCH(P, Q) family for monthly domestic price volatility of maize and teff crops, respectively. However, the volatility in the domestic price of wheat and barley was found to be not changing over time. Hence, the variance of the ARIMA process was used as the measure of volatility in the prices of these two crops which were 0.00112 and 0.0004, respectively. Moreover, it was found that from candidate exogenous variables, import prices for maize crop, fuel oil price, exchange rate (dollar-birr), inflation from non-food items, past shock and volatility on the domestic price had statistically significant effect on the current month domestic price volatility for maize and teff crops.

Published in International Journal of Data Science and Analysis (Volume 7, Issue 6)
DOI 10.11648/j.ijdsa.20210706.12
Page(s) 139-149
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Domestic Price Volatility, Time Series Data, ARCH, GARCH, EGARCH

References
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[2] Rashid, S. and Meron, A. (2007). Cereal Price Instability in Ethiopia: an Analysis of Sources and Policy Options. Paper prepared for the Agricultural Economics Association for Africa, Ghana.
[3] Yonas Alem and Mans Soderbom (2011). Household-Level Consumption in Urban Ethiopia: The Effects of a Large Food Price Shock, Working paper.
[4] Klugman, J. (2007). Explaining Food Price Inflation Policy Note. Discussion paper, Ethiopia.
[5] Myers, R. J. and Hanson, S. D. (1993). Pricing Commodity Options when the Underlying Futures Price Exhibits Time-Varying Volatility. American Journal of Agricultural Economics, vol. 75: p. 121–130.
[6] Dehn, J. (2000). Commodity Price Uncertainty in Developing Countries. Working paper at the Centre for the Study of African Economies.
[7] Jordaan, H., Jooste, B. A. and Alemu, Z. G. (2007). Measuring the Price Volatility of Certain Field Crops in South Africa using the ARCH/GARCH Approach. Journal of agriculture, Vol. 46.
[8] Box, G. and Jenkins, G. M. (1976). Time Series Analysis: Forecasting and Control, Revised Edition, Oakland, CA: Holden-Day.
[9] Nelson, D. (1991). Conditional Heteroskedasticity in Returns: a New Approach. Journals of Econometrics, vol. 59: p. 347-70.
[10] Phillips, C. B. and Perron, P. (1988). Testing for a Unit Root in Time Series Regression. Biometrics, vol. 75: p. 335–346.
[11] Dickey, D. A. and Fuller, W. A. (1979). Distribution of the Estimators for Autoregressive Time Series with a Unit Root. Journal of the American Statistical Association, vol. 74, p. 427–431.
[12] Asteriou, D. and Hall, S. G. (2007). Applied Econometrics: A Modern Approach Using Eviews and Microfit: Revised Edition, Hampshire, Palgrave Macmillan.
[13] Lee, C. L. (2009). Housing Price Volatility and its Determinants, School of Economics and Finance, University of Western Sydney, Australia.
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[16] Engle, R. F. (1982). Autoregressive Conditional Heteroskedasticity with Estimates of Variance of United Kingdom Inflation. Journals of Econometrics, vol. 50: P. 987–1007.
[17] Bollerslev, T. and Taylor, S. (1986). Generalized Autoregressive Conditional Heteroskedast-icity. Journal of Econometrics, vol. 31: p. 307–327.
[18] Akaike, H. (1974). A new look at the statistical model identification. IEEE Transactions on Automatic Control, AC-19, 716–723.
[19] Schwarz, Gideon E. (1978). Estimating the dimension of a model, Annals of Statistics, 6 (2): 461-464, doi: 10.1214/aos/1176344136, MR 0468014.
[20] McLeod, A. I. (1983). Diagnostic Checking ARMA Time Series Model Using Squared-Residual Autocorrelations. Journal of Time Series Analysis.
[21] Chatfield, C. (1989) The Analysis of Time Series: An Introduction. 4th Edition, Chapman and Hall, New York.
[22] Loening, J., Durevall, D. and Birru, Y. A. (2009). Inflation Dynamics and Food Prices in an Agricultural Economy: The Case of Ethiopia. World Bank Policy Research Working Paper Series, No. 4969.
[23] Gilbert, C. L. (1989). The Impact of Exchange Rates and Developing Country Debt on Commodity Prices. Journal of Economics, Vol. 99: p. 773–84.
[24] Chambers, R. G. and Just, R. E. (1984). Effects of Exchange Rate Changes on U.S. Agriculture. Journals of Agricultural Economics, vol. 73: p. 33-43.
[25] Swaray, R. (2007). How did the Demise of International Commodity Agreements Affect Volatility of Primary Commodity Prices? Applied Economics, No.#(17: p. 2253-2260.
[26] Baffes, J. (2007). Oil Spills on Other Commodities. World Bank Policy Research Working Paper.
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Cite This Article
  • APA Style

    Belay Belete Anjullo. (2021). Modeling Domestic Price Volatility for Cereal Crops in Ethiopia. International Journal of Data Science and Analysis, 7(6), 139-149. https://doi.org/10.11648/j.ijdsa.20210706.12

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    ACS Style

    Belay Belete Anjullo. Modeling Domestic Price Volatility for Cereal Crops in Ethiopia. Int. J. Data Sci. Anal. 2021, 7(6), 139-149. doi: 10.11648/j.ijdsa.20210706.12

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    AMA Style

    Belay Belete Anjullo. Modeling Domestic Price Volatility for Cereal Crops in Ethiopia. Int J Data Sci Anal. 2021;7(6):139-149. doi: 10.11648/j.ijdsa.20210706.12

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  • @article{10.11648/j.ijdsa.20210706.12,
      author = {Belay Belete Anjullo},
      title = {Modeling Domestic Price Volatility for Cereal Crops in Ethiopia},
      journal = {International Journal of Data Science and Analysis},
      volume = {7},
      number = {6},
      pages = {139-149},
      doi = {10.11648/j.ijdsa.20210706.12},
      url = {https://doi.org/10.11648/j.ijdsa.20210706.12},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijdsa.20210706.12},
      abstract = {The volatility in the domestic prices of maize and teff crops has been found to vary over time from month to month. Thus, Families of time series models namely, ARCH with their extensions to generalized ARCH, GARCH and EGARCH models with ARIMA mean equations were considered to the data. The best fitting model among each family of models was selected based on how well the model captures the variations in the data. The optimal lag specification for the models are accessed via AIC and SBIC. Comparisons of the symmetric and asymmetric selected models were carried out based on the significance of asymmetric term in the EGARCH model. Thus, statistically significance of asymmetric term and least forecast error from the model established that the EGARCH model with GED for residuals was superior to the GARCH model. Therefore, the ARIMA(2,0,3)-EGARCH(1,1) and ARIMA(0,0,3)-EGARCH(2,3) were chosen to be the best fitting models among the ARIMA(p, d, q)-GARCH(P, Q) family for monthly domestic price volatility of maize and teff crops, respectively. However, the volatility in the domestic price of wheat and barley was found to be not changing over time. Hence, the variance of the ARIMA process was used as the measure of volatility in the prices of these two crops which were 0.00112 and 0.0004, respectively. Moreover, it was found that from candidate exogenous variables, import prices for maize crop, fuel oil price, exchange rate (dollar-birr), inflation from non-food items, past shock and volatility on the domestic price had statistically significant effect on the current month domestic price volatility for maize and teff crops.},
     year = {2021}
    }
    

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  • TY  - JOUR
    T1  - Modeling Domestic Price Volatility for Cereal Crops in Ethiopia
    AU  - Belay Belete Anjullo
    Y1  - 2021/11/12
    PY  - 2021
    N1  - https://doi.org/10.11648/j.ijdsa.20210706.12
    DO  - 10.11648/j.ijdsa.20210706.12
    T2  - International Journal of Data Science and Analysis
    JF  - International Journal of Data Science and Analysis
    JO  - International Journal of Data Science and Analysis
    SP  - 139
    EP  - 149
    PB  - Science Publishing Group
    SN  - 2575-1891
    UR  - https://doi.org/10.11648/j.ijdsa.20210706.12
    AB  - The volatility in the domestic prices of maize and teff crops has been found to vary over time from month to month. Thus, Families of time series models namely, ARCH with their extensions to generalized ARCH, GARCH and EGARCH models with ARIMA mean equations were considered to the data. The best fitting model among each family of models was selected based on how well the model captures the variations in the data. The optimal lag specification for the models are accessed via AIC and SBIC. Comparisons of the symmetric and asymmetric selected models were carried out based on the significance of asymmetric term in the EGARCH model. Thus, statistically significance of asymmetric term and least forecast error from the model established that the EGARCH model with GED for residuals was superior to the GARCH model. Therefore, the ARIMA(2,0,3)-EGARCH(1,1) and ARIMA(0,0,3)-EGARCH(2,3) were chosen to be the best fitting models among the ARIMA(p, d, q)-GARCH(P, Q) family for monthly domestic price volatility of maize and teff crops, respectively. However, the volatility in the domestic price of wheat and barley was found to be not changing over time. Hence, the variance of the ARIMA process was used as the measure of volatility in the prices of these two crops which were 0.00112 and 0.0004, respectively. Moreover, it was found that from candidate exogenous variables, import prices for maize crop, fuel oil price, exchange rate (dollar-birr), inflation from non-food items, past shock and volatility on the domestic price had statistically significant effect on the current month domestic price volatility for maize and teff crops.
    VL  - 7
    IS  - 6
    ER  - 

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Author Information
  • Department of Statistics, Arba Minch University, Arba Minch, Ethiopia

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