The influence of regional integration on inflation volatility: Evidence from Tanzania in the East African community (EAC)
DOI:
https://doi.org/10.51867/AQSSR.3.2.31Keywords:
ARCH/GARCH Models, EGARCH Asymmetry, East African Community (EAC), Inflation Volatility, Regional Integration, TanzaniaAbstract
This study examines how East African Community (EAC) regional integration influences inflation volatility in Tanzania. We use the Autoregressive Conditional Heteroskedastic (ARCH) and Generalised Autoregressive Conditional Heteroskedastic (GARCH) family of models to describe the conditional variance dynamics. This study is guided by Mundell's Optimum Currency Area (OCA) theory, which suggests that sharing a currency decreases inflation volatility via policy coordination by increasing shock absorption due to labour and capital mobility and requiring symmetry among economic partners. Employing quarterly time-series data over critical integration periods, including the attainment of the Customs Union in 2005 and the Common Market in 2010, the findings show that regional integration reduces inflation volatility by encouraging trade convergence, improving monetary coordination, and strengthening expectation anchors. Under the Exponential Generalised Autoregressive Conditional Heteroskedasticity (EGARCH) specifications, the estimated asymmetry and persistence parameters were found to be statistically significant, with integration reforms accounting for approximately 79% of quarterly volatility carryover. After 2005, mean-stable inflation with an average of around 1% characterises Tanzania, in contrast to persistently high inflation. However, post-reform turbulence and clustering of volatility point towards the risk of external shocks as a vulnerability for emerging markets aligned with commodity shocks. The results support the conclusions from the optimum currency area (OCA) theory, suggesting that integration fosters convergence and stabilisation, while revealing structural asymmetries such as the agrarian reliance on Tanzania and manufacturers’ tilt of Kenya, which are magnets for uneven volatility among member states. The policy implications of these findings advocate for the rapid operationalisation of the EAC Monetary Union, stronger fiscal surveillance, trade diversification, and the increased sophistication of econometric frameworks. Through enhanced integration that also tackles structural weaknesses, Tanzania and the EAC can create an environment in which inflation variability is a controllable risk rather than an insurmountable barrier to continued economic expansion. Building on these implications, this study recommends strengthening regional stabilisation mechanisms, such as dedicated stabilisation funds; enhancing agricultural productivity to reduce food price volatility; and deepening financial market development to improve monetary transmission. In addition, investing in cross-border infrastructure supports supply chain resilience, and adopting joint inflation-forecasting frameworks enables policymakers to anticipate and mitigate external shocks. Collectively, these measures will reinforce the foundations of integration and culminate in a successful monetary union (MU).
References
Adam, C. S., & Bevan, D. (2015). Fiscal reforms and public investment in Africa. Journal of African Economies, 24(Suppl. 2), ii16-ii42. https://doi.org/10.1093/jae/eju039
Adam, C. S., Collier, P., & Ndung'u, N. S. (Eds.). (2010). Kenya: Policies for prosperity. Oxford University Press.
Adeleke, A. I. (2022). Exchange rate dynamics and regional trade integration in the West African Monetary Zone (WAMZ) (WAMI Occasional Paper Series No. 28). West African Monetary Institute. https://wami-imao.org/sites/default/files/202403/OPS%2028_Exchange%20rate%20dynamics%20and%20regional%20trade%20integration%20in%20the%20WAMZ__Final.pdf
African Development Bank. (2024). East Africa economic outlook 2024. African Development Bank Group. https://www.afdb.org/sites/default/files/documents/publications/reo_east_africa_english_2024.pdf
Anyanwu, J. (2012). Why does foreign direct investment go where it goes? New evidence from African countries. Annals of Economics and Finance, 13(2), 425-462. http://aeconf.com/Articles/Nov2012/aef130207.pdf
Babayemi, A. W., & Odunaiya, S. O. (2021). Cross-border activities, financial development and exchange rate volatilities in Nigeria and its bordering countries. Science Journal of Advanced and Cognitive Research, 2(2), 1-12. https://www.bibliomed.org/?mno=110679
Bahmani-Oskooee, M., & Ratha, A. (2004). The J-curve: A literature review. Applied Economics, 36(13), 1377-1398.
https://doi.org/10.1080/0003684042000201794
Bai, J., & Perron, P. (1998). Estimating and testing linear models with multiple structural changes. Econometrica, 66(1), 47-78. https://doi.org/10.2307/2998540
Bai, J., & Perron, P. (2003). Computation and analysis of multiple structural change models. Journal of Applied Econometrics, 18(1), 1-22. https://doi.org/10.1002/jae.659
Balassa, B. (1961). The theory of economic integration. Allen & Unwin.
Balassa, B. (1964). The purchasing power parity doctrine: A reappraisal. Journal of Political Economy, 72(6), 584-596. https://doi.org/10.1086/258965
Bayoumi, T., & Eichengreen, B. (1994). One money or many? Analysing the prospects for monetary unification in various parts of the world (Princeton Studies in International Finance No. 76). Princeton University. https://www.princeton.edu/~ies/IES_Essays/E76.pdf
Becker, R., Hall, S., & Rustem, B. (1994). Robust optimal decisions with stochastic nonlinear economic systems. Journal of Economic Dynamics and Control, 18(1), 125-147. https://doi.org/10.1016/0165-1889(94)90072-8
Beetsma, R., & Giuliodori, M. (2010). The macroeconomic costs and benefits of the EMU and other monetary unions: An overview of recent research. Journal of Economic Literature, 48(3), 603-641. https://doi.org/10.1257/jel.48.3.603
Bollerslev, T. (1986). Generalised autoregressive conditional heteroskedasticity. Journal of Econometrics, 31(3), 307-327.
https://doi.org/10.1016/0304-4076(86)90063-1
Buigut, S. K., & Valev, N. T. (2005). Is the proposed East African Monetary Union an optimal currency area? A structural vector autoregression analysis. World Development, 33(12), 2119-2133. https://doi.org/10.1016/j.worlddev.2005.06.006
Calderón, C., Chong, A., & Stein, E. (2007). Trade intensity and business cycle synchronisation: Are developing countries any different? Journal of International Economics, 71(1), 2-21. https://doi.org/10.1016/j.jinteco.2006.06.001
Coulibaly, S. (2006). Regional integration and the persistent uneven spread of economic activities in developing areas. Economie Internationale, 106(2), 5-23. https://doi.org/10.3917/ecoi.106.0005
De Grauwe, P. (1988). Exchange rate variability and the slowdown in growth of international trade. IMF Staff Papers, 35(1), 63-84. https://www.elibrary.imf.org/view/journals/024/1988/001/article-A003-en.xml
https://doi.org/10.2307/3867277
De Grauwe, P. (2022). Economics of monetary union (4th ed.). Oxford University Press.
De Grauwe, P., & Mongelli, F. P. (2005). Endogeneities of optimum currency areas: What brings countries sharing a single currency closer together? (ECB Working Paper Series No. 468). European Central Bank. https://doi.org/10.2139/ssrn.691864
De Melo, J., & Tsikata, Y. (2014). Regional integration in Africa: Challenges and prospects (WIDER Working Paper No. 2014/037). UNU-WIDER. https://doi.org/10.35188/UNU-WIDER/2014/758-5
Dickey, D. A., & Fuller, W. A. (1979). Distribution of the estimators for autoregressive time series with a unit root. Journal of the American Statistical Association, 74(366a), 427-431. https://doi.org/10.2307/2286348
Dobronogov, A., & Farole, T. (2012). An economic integration zone for the East African Community (Policy Research Working Paper No. 5967). World Bank. https://openknowledge.worldbank.org/handle/10986/3253
Dridi, J., & Nguyen, A. D. M. (2019). Assessing inflation convergence in the East African Community. Journal of International Development, 31(2), 119-136. https://doi.org/10.1002/jid.3396
Drummond, P., & Liu, E. X. (2013). Africa's rising exposure to China: How large are the spillovers through trade? (IMF Working Paper No. 13/250). International Monetary Fund. https://www.imf.org/external/pubs/ft/wp/2013/wp13250.pdf
https://doi.org/10.5089/9781484311318.001
Drummond, P., Aisen, A., Alper, E., Fuli, E., & Walker, S. (2015). Toward a monetary union in the East African Community (African Departmental Paper). International Monetary Fund. https://www.imf.org/external/pubs/ft/dp/2015/afr1506.pdf
Drummond, P., Wajid, S. K., & Williams, O. (Eds.). (2015). The quest for regional integration in the East African Community. International Monetary Fund. https://doi.org/10.5089/9781484364413.071
East African Community Secretariat. (2024). EAC trade and investment report 2023: Structural transformation for trade and investment facilitation for increasing regional economic growth, productivity and resilience. East African Community Secretariat. https://research.trademarkafrica.com/wp-content/uploads/2024/10/EAC-Trade-and-Investment-Report-2023-compressed.pdf
East African Community. (2013). Protocol on the establishment of the East African Community Monetary Union. EAC Secretariat. https://www.eac.int/documents/category/monetary-union-protocol
Edwards, S. (1998). Openness, productivity, and growth: What do we really know? Economic Journal, 108(447), 383-398. https://doi.org/10.1111/1468-0297.00293
Ejones, F., Agbola, F. W., & Mahmood, A. (2021). Regional integration and economic growth: New empirical evidence from the East African Community. The International Trade Journal, 35(4), 311-335. https://doi.org/10.1080/08853908.2021.1880990
Engle, R. F. (1982). Autoregressive conditional heteroscedasticity with estimates of the variance of United Kingdom inflation. Econometrica, 50(4), 987-1007. https://doi.org/10.2307/1912773
Engle, R. F., Ghysels, E., & Sohn, B. (2013). Stock market volatility and macroeconomic fundamentals. Review of Economics and Statistics, 95(3), 776-797. https://doi.org/10.1162/REST_a_00300
European Central Bank. (2015). Economic bulletin (Issue 1/2015). European Central Bank. https://www.ecb.europa.eu/pub/pdf/ecbu/eb201501.en.pdf
Fischer, S. (1993). The role of macroeconomic factors in growth. Journal of Monetary Economics, 32(3), 485-512. https://doi.org/10.1016/0304-3932(93)90027-D
Frankel, J. A., & Rose, A. K. (1998). The endogeneity of the optimum currency area criteria. Economic Journal, 108(449), 1009-1025. https://doi.org/10.1111/1468-0297.00327
Frenkel, J. A., & Rose, A. K. (2000). Estimating the effect of currency unions on trade and output (NBER Working Paper No. 7857). National Bureau of Economic Research. https://doi.org/10.3386/w7857
Gammadigbe, V. (2021). Is regional trade integration a growth and convergence engine in Africa? (IMF Working Paper No. 2021/019). International Monetary Fund. https://www.imf.org/en/publications/wp/issues/2021/01/29/is-regional-trade-integration-a-growth-and-convergence-engine-in-africa-50040
https://doi.org/10.5089/9781513567716.001
Grier, K. B., & Perry, M. J. (2000). The effects of real and nominal uncertainty on inflation and output growth: Some GARCH-M evidence. Journal of Applied Econometrics, 15(1), 45-58. https://doi.org/10.1002/(SICI)1099-1255(200001/02)15:1<45::AID-JAE542>3.0.CO;2-K
https://doi.org/10.1002/(SICI)1099-1255(200001/02)15:1<45::AID-JAE542>3.0.CO;2-K
Grossman, G. M., & Helpman, E. (1991). Innovation and growth in the global economy. MIT Press. https://mitpress.mit.edu/9780262071369/innovation-and-growth-in-the-global-economy/
International Monetary Fund. (2017). Regional economic outlook: Sub-Saharan Africa - Restarting the growth engine. International Monetary Fund. https://www.imf.org/-/media/Files/Publications/REO/AFR/2017/May/pdf/sreo0517.ashx
International Monetary Fund. (2021). West African Economic and Monetary Union: Staff report on common policies for member countries-Press release; staff report; and statement by the executive director for the West African Economic and Monetary Union (IMF Country Report No. 21/049). https://www.imf.org/en/Publications/CR/Issues/2021/03/02/West-African-Economic-and-Monetary-Union-Staff-Report-on-Common-Policies-for-Member-50140
https://doi.org/10.5089/9781513570983.002
Jarque, C. M., & Bera, A. K. (1987). A test for normality of observations and regression residuals. International Statistical Review, 55(2), 163-172. https://doi.org/10.2307/1403192
Kasekende, L., & Brownbridge, M. (2011). Post-crisis monetary policy frameworks in Sub-Saharan Africa. African Development Review, 23(2), 190-201. https://doi.org/10.1111/j.1467-8268.2011.00280.x
Kessy, P. (2011). Dollarization in Tanzania: Empirical evidence and cross-country experience (IGC Working Paper). International Growth Centre. https://www.theigc.org/sites/default/files/2014/09/Kessy-2011-Working-Paper.pdf
Kimolo, D. W., Budeba, M. S., & Mafie, G. K. (2025). Exchange rate pass-through to inflation in Tanzania (Bank of Tanzania Working Paper No. 39). Bank of Tanzania. https://www.bot.go.tz/Publications/Other/Working%20Papers%20Series/en/2026022710484188.pdf
Kose, M. A., Prasad, E. S., & Terrones, M. E. (2003). Financial integration and macroeconomic volatility. IMF Staff Papers, 50(1), 119-142.
https://doi.org/10.2307/4149918
Krugman, P. (1991). Increasing returns and economic geography. Journal of Political Economy, 99(3), 483-499. https://doi.org/10.1086/261763
Mafusire, A., & Brixiova, Z. (2013). Macroeconomic shock synchronisation in the East African Community. Global Economy Journal, 13(2), 261-280. https://doi.org/10.1515/gej-2013-0015
Makochekanwa, A., Hurungo, J. T., & Kambarami, P. (2012). Zimbabwe's experience with trade liberalization (AERC Research Paper No. 245). African Economic Research Consortium. https://publication.aercafricalibrary.org/bitstreams/81c069c7-1de7-4663-a701-ea2c7bf82770/download
Mbwambo, S. K., & Mchukwa, E. W. (2024). The effects of exchange rate volatility and inflation on Tanzania's trade balance: Evidence from the J-curve effect. East African Journal of Business and Economics, 7(2), 1-15. https://doi.org/10.37284/eajbe.7.2.2504
McGettigan, D., Moriyama, K., Ntsama, J. N. N., Painchaud, F., Qu, H., & Steinberg, C. (2013). Monetary policy in emerging markets: Taming the cycle (IMF Working Paper No. 13/96). International Monetary Fund. https://www.imf.org/external/pubs/ft/wp/2013/wp1396.pdf
https://doi.org/10.5089/9781484381847.001
McIntyre, M. A. (2005). Trade integration in the East African Community: An assessment for Kenya (IMF Working Paper No. 05/143). International Monetary Fund. https://www.imf.org/external/pubs/ft/wp/2005/wp05143.pdf
https://doi.org/10.5089/9781451861624.001
Melina, G., & Portillo, R. (2018). Economic fluctuations in Sub-Saharan Africa (IMF Working Paper No. 18/40). International Monetary Fund. https://www.elibrary.imf.org/downloadpdf/journals/001/2018/040/article-A000-en.pdf
https://doi.org/10.5089/9781484344880.001
Melitz, M. (2003). The impact of trade on intra-industry reallocations and aggregate industry productivity. Econometrica, 71(6), 1695-1725. https://doi.org/10.1111/1468-0262.00467
Mosbei, T., Samoei, S. K., Tison, C. C., & Kipchoge, E. K. (2021). Exchange rate volatility and its effect on intra-East Africa Community regional trade. Latin American Journal of Trade Policy, 4(9), 43-53. https://doi.org/10.5354/0719-9368.2021.58790
Mose, N. G. (2019). Does inflation rate convergence spur exchange rate volatility? Evidence from Sub-Saharan Africa. Asian Journal of Economic Modelling, 7(2), 95-109. https://doi.org/10.18488/journal.8.2019.72.95.109
Mundell, R. A. (1961). A theory of optimum currency areas. American Economic Review, 51(4), 657-665. https://www.aeaweb.org/aer/top20/51.4.657-665.pdf
Mundell, R. A. (1963). Capital mobility and stabilisation policy under fixed and flexible exchange rates. Canadian Journal of Economics and Political Science, 29(4), 475-485. https://doi.org/10.2307/139336
National Bureau of Statistics. (2025). National consumer price index (NCPI) for July 2025. National Bureau of Statistics. https://www.nbs.go.tz/uploads/statistics/documents/en-1754909105-CPI%20%20Release_072025_English.pdf
National Bureau of Statistics. (2025a). Tanzania's inflation trends in August 2025. TICGL. https://ticgl.com/tanzanias-inflation-trends-in-august-2025/
Nelson, D. B. (1991). Conditional heteroskedasticity in asset returns: A new approach. Econometrica, 59(2), 347-370. https://doi.org/10.2307/2938260
Ng'eno, K., Nyangito, H., Ikiara, M., Ronge, E., & Nyamunga, J. (2003). Regional integration study of East Africa: The case of Kenya (KIPPRA Working Paper No. 9). Kenya Institute for Public Policy Research and Analysis. https://repository.kippra.or.ke/bitstreams/1ea07e31-43cf-4998-b4b4-6a27013f794a/download
Ngailo, E., Luvanda, E., & Massawe, E. S. (2014). Time series modelling with application to Tanzania inflation data. Journal of Data Analysis and Information Processing, 2(2), 49-59. https://doi.org/10.4236/jdaip.2014.22007
Nzioka, O. M., Kaijage, E., & Ochieng, D. E. (2017). Financial integration, macroeconomic volatility, and economic growth in the East African Community. European Scientific Journal, 13(19), 317. https://doi.org/10.19044/esj.2017.v13n19p317
Ogbuabor, J. E., Anthony-Orji, O. I., Ogbonna, O. E., & Orji, A. (2019). Regional integration and growth: New empirical evidence from WAEMU. Progress in Development Studies, 19(2), 123-143. https://doi.org/10.1177/1464993418822883
Opolot, J., & Mpagi, A. (2017). Inflation dynamics in Uganda: The role of disequilibria in the money and traded goods markets. Journal of Statistical and Econometric Methods, 6(1), 1-2. http://www.scienpress.com/Upload/JSEM%2fVol%206_1_2.pdf
Peter, M., Mirau, S., Sinkwembe, E., Kasumo, C., & Guambe, C. (2025). Symmetric and asymmetric GARCH estimations of the impact of macroeconomic uncertainties on stock market dynamics in Tanzania. Future Business Journal, 11(1), 203. https://doi.org/10.1186/s43093-025-00632-5
Rose, A. K. (2000). One money, one market: The effect of common currencies on trade. Economic Policy, 15(30), 7-46.
https://doi.org/10.1111/1468-0327.00056
Samuelson, P. A. (1964). Theoretical notes on trade problems. Review of Economics and Statistics, 46(2), 145-154.
https://doi.org/10.2307/1928178
Southern African Development Community. (2018). SADC annual report 2017/18. SADC Secretariat. https://www.sadc.int/sites/default/files/2021-07/Annual_Report_2017_-_2018_EN.pdf
Woodford, M. (2003). Interest and prices: Foundations of a theory of monetary policy. Princeton University Press. https://doi.org/10.1515/9781400830169
World Bank. (2024). Inflation, consumer prices (annual %) - Tanzania [Data set]. Retrieved March 5, 2026, from https://data.worldbank.org/indicator/FP.CPI.TOTL.ZG?locations=TZ
Yabu, N., & Kessy, N. J. (2015). Appropriate threshold level of inflation for economic growth: Evidence from the three founding EAC countries. Applied Economics and Finance, 2(3), 127-144. https://doi.org/10.11114/aef.v2i3.966
Yussif, A. B., Onifade, S. T., Ay, A., Canitez, M., & Bekun, F. V. (2024). Modeling the volatility of exchange rate and international trade in Ghana: Empirical evidence from GARCH and EGARCH. Journal of Economic and Administrative Sciences, 40(2), 308-324. https://doi.org/10.1108/JEAS-11-2020-0187
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