Abstract
International poverty estimates for countries in Africa commonly rely on national consumer price indexes to adjust trends in nominal consumption over time for changes in the cost of living. However, the consumer price index is subject to various types of measurement bias. This paper uses Engel curve estimations to assess bias in the consumer price index and its implications for estimated poverty trends. The results suggest that in 13 of 16 Sub-Saharan African countries in this study, poverty reduction may be understated because of consumer price index bias. With correction of consumer price index bias, poverty in these countries could fall between 0.4 and 5.2 percentage points per year faster than currently thought. For two countries, however, the paper finds the opposite trend. There is no statistically significant change in poverty patterns after adjusting for consumer price index bias for only one country.
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References
Almas, I.: International income inequality: measuring PPP Bias by estimating Engel curves for food. Am. Econ. Rev. 102(1), 1093–1117 (2012)
Almas, I., Beatty, T., Crossley, T.: “Lost in translation: what do Engel curves tell us about the cost of living?” IFS working paper 18/04. Institute for Fiscal Studies (IFS), London (2018)
Almas, I., Kjelsrud, A., Somanathan, R.: A behavior-based approach to the estimation of poverty in India. Scand. J. Econ. 121(1), 182–224 (2019)
Barrett, G.F., Brzozowski, M.: Using Engel curves to estimate the Bias in the Australian CPI. Econ. Rec. 86(272), 1–14 (2010)
Beatty, T., Larsen, E.: Using Engel curves to estimate Bias in the Canadian CPI as a cost of living index. Can. J. Econ. 38(2), 482–499 (2005)
Beegle, K., Christiaensen, L., Dabalen, A., Gaddis, I.: Poverty in a Rising Africa. World Bank, Washington, DC (2016)
Boskin, M.J., Dulberger, E.R., Gordon, R.J., Griliches, Z., Jorgenson, D.W.: Toward a more Accurate Measure of the Cost of Living: Final Report. Senate Finance Committee, Washington, DC (1996) http://www.ssa.gov/history/reports/boskinrpt.html
Boskin, M.J., Dulberger, E.R., Gordon, R.J., Griliches, Z., Jorgenson, D.W.: Consumer prices, the consumer Price index, and the cost of living. J. Econ. Perspect. 12(1), 3–26 (1998)
Brzozowski, M.: Does one size fit all? The CPI and Canadian seniors. Can. Public Policy. 32(4), 387–412 (2006)
Chamon, M., De Carvalho Filho, I.: Consumption based estimates of urban Chinese growth. China Econ. Rev. 29, 126–137 (2014)
Chung, C., Gibson, J., Kim, B.: CPI mismeasurements and their impacts on economic Management in Korea. Asian Economic Papers. 9(1), 1–15 (2010)
Coondoo, D., Majumder, A., Chattopadhyay, S.: Estimating spatial consumer Price indices through Engel curve analysis. Rev. Income Wealth. 57(1), 138–155 (2011)
Costa, D.L.: Estimating real income in the United States from 1888 to 1994: correcting CPI Bias using Engel curves. J. Polit. Econ. 109(6), 1288–1310 (2001)
De Carvalho Filho, I., Chamon, M.: The myth of post-reform income stagnation: evidence from Brazil and Mexico. J. Dev. Econ. 97(2), 368–386 (2012)
Deaton, A.: The Analysis of Household Surveys: a Microeconometric Approach to Development Policy. Johns Hopkins University Press, Baltimore (1997)
Deaton, A.: Getting prices right: what should be done? J. Econ. Perspect. 12(1), 37–46 (1998)
Demombynes, G., Trommlerová, S.K.: What has driven the decline of infant mortality in Kenya in the 2000s? Econ. Hum. Biol. 21, 17–32 (2016)
Feenstra, R., Reinsdorf, M.: An exact Price index for the almost demand system. Econ. Lett. 66, 159–162 (2000)
Frisch, R.: A complete scheme for computing all direct and cross demand elasticities in a model with many sectors. Econometrica. 27(2), 177–196 (1959)
Gaddis, I.: Prices for poverty analysis in Africa. In: Policy Research Working Paper 7652. Washington D.C, World Bank (2016)
Gibson, J., Scobie, G.: Using Engel curves to estimate CPI Bias in a small, open, inflation-targeting economy. Appl. Financ. Econ. 20(17), 1327–1335 (2010)
Gibson, J., Stillman, S., Le, T.: CPI Bias and real living standards in Russia during the transition. J. Dev. Econ. 87(1), 140–160 (2008)
Gibson, J., Le, T., Kim, B.: Prices, Engel curves and time-space deflation: impacts on poverty and inequality in Vietnam. World Bank Econ. Rev. 31(2), 504–530 (2017)
Gorry, J., Scrimgeour, D.: Using Engel curves to estimate CPI Bias for the elderly. Contemp. Econ. Policy. 36(3), 539–553 (2018)
Greenlees, John S. Expenditure Weight Updates and Measured Inflation (1997). Retrieved from: http://www.ottawagroup.org/Ottawa/ottawagroup.nsf/home/Meeting+3/$file/1997%203rd%20Meeting%20-%20Greenlees%20John%20-%20Expenditure%20weight%20updates%20and%20measured%20inflation.pdf
Günther, I., Grimm, M.: Measuring pro-poor growth when relative prices shift. J. Dev. Econ. 82(1), 245–256 (2007)
Hamilton, B.W.: Using Engel’s law to estimate CPI Bias. Am. Econ. Rev. 91(3), 619–630 (2001)
Harttgen, K., Klasen, S., Vollmer, S.: An African growth miracle? Or: what do asset indices tell us about trends in economic performance? Rev. Income Wealth. 59(October), S37–S61 (2013a)
Harttgen, K., Klasen, S., Vollmer, S.: Economic growth and child undernutrition in sub-Saharan Africa. Popul. Dev. Rev. 39(3), 397–412 (2013b)
Hausman, J.: Sources of Bias and solutions to Bias in the consumer Price index. J. Econ. Perspect. 17(1), 23–44 (2003)
ILO (International Labour Organization): All Countries CPI Descriptions: Methodologies of Compiling Consumer Price Indices. 2012 ILO Survey of Country Practices. ILO, Geneva (2013)
Kaplan, G., Schulhofer-Wohl, S.: Inflation at the household level. J. Monet. Econ. 91, 19–38 (2017)
Kenny, C.: Getting Better: why Global Development Is Succeeding and how we Can Improve the World Even More. Basic Books, New York (2011)
Kokoski, Mary. Alternative CPI aggregations: two approaches. Monthly Labor Review (November): 31-9 (2000)
Lange, S., Klasen, S.: How the new international goal for child mortality is unfair to sub-Saharan Africa (again). World Dev. 90, 128–146 (2017)
Larsen, E.: Does the CPI Mirror the cost of living? Engel’s law suggests not in Norway. Scand. J. Econ. 109(1), 177–195 (2007)
Lluch, Constantino, Alan A. Powell, and Ross Williams. Patterns in household demand and saving. Washington, DC: World Bank; New York: Oxford University Press (1977)
Logan, T.D.: Are Engel curve estimates of CPI Bias biased? Hist. Metall. 42(3), 97–109 (2009)
Nakamura, E., Steinsson, J., Liu, M.: Are Chinese growth and inflation too smooth? Evidence from Engel curves. Am. Econ. J. Macroecon. 8(3), 113–144 (2016)
Nicholson, J.L.: Whose cost of living? Journal of the Royal Statistical Society. Series A (General). 138(4), 540–542 (1975)
Olivia, S., Gibson, J.: Using Engel curves to measure CPI Bias for Indonesia. Bull. Indones. Econ. Stud. 49(1), 85–101 (2013)
Pinkovskiy, M., Sala-i-Martin, X.: Africa is on time. J. Econ. Growth. 19(3), 311–338 (2014)
Pollak, R.A.: The consumer Price index: a research agenda and three proposals. J. Econ. Perspect. 12(1), 69–78 (1998)
Prais, S.J.: Whose cost of living? Rev. Econ. Stud. 26(2), 126–134 (1959)
Ravallion, M.: Poverty lines in theory and practice. Living Standards Measurement Study (LSMS) Working Paper 133. World Bank, Washington, DC (1998)
Sandefur, Justin. Africa Rising? Using Micro Surveys to Correct Macro Time Series (2013). Retrieved from: http://www.worldbank.org/content/dam/Worldbank/Feature%20Story/Africa/afr-justin-sandefur.pdf
Schultze, C.L., Mackie, C.: At What Price? Conceptualizing and Measuring Cost-of-Living and Price Indexes. National Academy Press, Washington, DC (2002)
Shapiro, M.D., Wilcox, D.W.: Mismeasurement in the consumer Price index: an evaluation. In: Bernanke, B.S., Rotemberg, J.J. (eds.) NBER Macroeconomics Annual 1996, vol. 11, pp. 105–106. MIT Press, Cambridge (1996)
Tanzania NBS (National Bureau of Statistics): Methodology for compilation of National Consumer Price Index (NCPI), Tanzania mainland. In: NBS, Ministry of Finance and Economic Affairs. Salaam, Tanzania, Dar es (2010)
United Nations: Practical Guide to Producing Consumer Price Indices. United Nations, New York (2009)
World Bank: Nigeria: where has all the growth gone? A policy note. Report no. 78908. World Bank, Washington DC (2014)
World Bank. United Republic of Tanzania. Tanzania mainland poverty assessment. Report no. AUS6819. World Bank, Washington DC (2015)
Young, A.: The African growth miracle. J. Polit. Econ. 120(4), 696–739 (2012)
Acknowledgments
We thank Kathleen Beegle, Jennifer Cisse, Luc Christiaensen, Jed Friedman, John Gibson, an anonymous reviewer as well as participants at various conferences for invaluable comments. We are also grateful to the national statistical offices of the countries used in this study for sharing the price data. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of The World Bank, its Board of Executive Directors, or the governments they represent. Of course, all errors are our own.
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Dabalen, A., Gaddis, I. & Nguyen, N.T.V. CPI Bias and its Implications for Poverty Reduction in Africa. J Econ Inequal 18, 13–44 (2020). https://doi.org/10.1007/s10888-019-09429-3
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DOI: https://doi.org/10.1007/s10888-019-09429-3