Is CPI generated from stationary process? An investigation on unit root hypothesis of India’s CPI

Azimi, Mohammad Naim (2015): Is CPI generated from stationary process? An investigation on unit root hypothesis of India’s CPI. Published in: International Journal of Management and Commerce Innovations , Vol. 3, No. 2 (1 February 2016): pp. 329-335.

Abstract

In this paper, the Consumer Price Index (CPI) of India is tested on whether it is generated from a stationary process for the purpose of which, a set of time series data on CPI with 4,420 observation arranged on daily basis from November 10, 2003 to December 16, 2015 is retrieved from the official website of National Bureau of Economic Research. The testing procedure includes fitted OLS regression on which the Augmented Dickey Fuller (ADF) and Phillips-Perron (PP) unit root test are computed. The statistical analysis of both ADF and PP exhibit a smaller test statistic value for CPI than the critical value at 0.05 which means that CPI is not generated from a stationary process and it follows unit root at level, though, it does not follow unit root and it is stationary at its first difference. Therefore, we reject the null hypothesis in favor of the alternative.

• Item Type: MPRA Paper
• Language: English
• Keywords: CPI; Unit Root; Stationary Process; Augmented Dickey Fuller; Philips-Perron
• Subjects: C - Mathematical and Quantitative Methods > C1 - Econometric and Statistical Methods and Methodology: General; C - Mathematical and Quantitative Methods > C1 - Econometric and Statistical Methods and Methodology: General > C12 - Hypothesis Testing: General; C - Mathematical and Quantitative Methods > C4 - Econometric and Statistical Methods: Special Topics > C41 - Duration Analysis ; Optimal Timing Strategies

References

[1] J. Barjis, “CPI modeling: Collaborative, participative, interactive modeling,” Proc. - Winter Simul. Conf., no. Barjis 2009, pp. 3094–3103, 2011.

[2] T. I. Garner, D. S. Johnson, and M. F. Kokoski, “An Experimental Consumer Price Index for the Poor,” Mon. Labor Rev., vol. 119, no. 9, pp. 32–42, 1996.

[3] A. DOUGHERTY and R. VAN-ORDER, “INFLATION, HOUSING COSTS, AND THE CONSUMER PRICE INDEX,” Am. Econ. Rev., vol. 72, pp. 154–164, 1982.

[4] L. E. Bolton, L. Warlop, and J. W. Alba, “Consumer Perceptions of Price (Un)Fairness,” J. Consum. Res., vol. 29, no. 4, pp. 474–491, 2003.

[5] I. Sinha and R. Batra, “The effect of consumer price consciousness on private label purchase,” Int. J. Res. Mark., vol. 16, no. 3, pp. 237–251, 1999.

[6] W. E. Diewert, “Index Number Issues in the Consumer Price Index,” J. Econ. Perspect., vol. 12, no. 1, pp. 47–58, 1998.

[7] D. J. B. Mitchell, “Should the Consumer Price Index Determine Wages?,” Calif. Manage. Rev., vol. 25, no. 1, pp. 5–21, 1982.

[8] K. Adekunle, “Exchange Rates and the Consumer Price Index in Nigeria : A Causality Approach,” J. Emerg. Trends Econ. Manag. Sci., vol. 1, no. 2, pp. 114–120, 2010.

[9] S. Saha and Z. Zhang, “Do exchange rates affect consumer prices? A comparative analysis for Australia, China and India,” Math. Comput. Simul., vol. 93, pp. 128–138, 2013.

[10] D. Grewal and J. Baker, “Do retail store environmental factors affect consumers’ price acceptability? An empirical examination,” Int. J. Res. Mark., vol. 11, no. 2, pp. 107–115, 1994.

[11] W. Diewert, “The Consumer Price Index and index number purpose,” J. Econ. Soc. Meas., vol. 27, no. 00, pp. 167–248, 2001.

[12] M. N. Azimi, “A Unit Root Hypothesis: Is Afghanistan Real GDP per Capita Stationary?,” J. Econ. Bus. Res., vol. 1, no. 1, pp. 1–6, 2015.

[13] W. A. Dicky, D.A. & Fuller, “Distribution of Estimates for Autoregressive Time Series with a Unit Root,” J. Am. Stat. Assoc., vol. 74, pp. 427–431, 1979.

[14] D. A. Dickey and W. A. Fuller, “Distribution of the estimators for autoregressive time series with a unit root.,” J. th Am. Stat. Assoc., vol. 74, no. 366a, pp. 427–431, 1979.

[15] J. G. Mackinnon, “Approximate Asymptotic Distribution Functions for Unit-Root and Cointegration Tests,” J. Bus. Econ. Stat., vol. 12, no. 2, pp. 167–176, 1994.

[16] C. F. Baum, “The Language of Choice for Time Series Analysis,” Stata J., vol. 5, pp. 46–63, 2005.

[17] P. C. Phillips and P. Perron, “Testing for a unit root in time series regression.,” Biometrika, vol. 75, no. 2, pp. 335–346, 1988.

[18] W. K. Newey and K. D. West, “A Simple, Positive Semi-definite, Heteroskedasticity and Autocorrelation Consistent Covariance Matrix,” Econom., vol. 55, no. 3, pp. 703–708, 1987.

[19] B. ~P. ~M. McCabe and A. ~R. Tremayne, “Testing a Time Series for Difference Stationarity,” Ann. Stat., vol. 23, pp. 1015–1028, 1995.

[20] P. Perron, “Testing for a Unit Root in a Time Series with a Changing Mean,” J. Bus. Econ. Stat., vol. 8, no. 2, pp. 153–162, 1990.

[21] B. Y. D. a Dickey and W. a Fuller, “Likelihood Ratio Statistics for Autoregressive Time Series with a Unit Root,” Econometrica, vol. 49, no. 4, pp. 1057–1072, 1981.

[22] P. Saikkonen and H. Lütkepohl, “Testing for a Unit Root in a Time Series With a Level Shift At Unknown Time,” Econom. Theory, vol. 18, no. 02, 2002.

[23] K. S. Im, M. H. Pesaran, and Y. Shin, “Testing for unit roots in heterogeneous panels,” J. Econom., vol. 115, no. 1, pp. 53–74, 2003.

[24] D. Romero-Ávila and C. Usabiaga, “The hypothesis of a unit root in OECD inflation revisited,” J. Econ. Bus., vol. 61, no. 2, pp. 153–161, 2009.

[25] R. D. E. M. Etodos, C. Para, and I. a Y. L. a Empresa, “Unit Root Tests and Structural Breaks: A Survey with Applications,” J. Quant. Methods Econ. Bus. Adm., vol. 3, no. 1, pp. 63–79, 2007.