Abstract
It is argued if xt ~ I(1) and yt ~ I(1), then running a regression xt on yt would produce spurious results because e t would generally be I(1). However, there may exist a ‘b’ such that e t = x t - by t is I(0), then running a regression x t on y t would not produce spurious results. This special case of two integrated time series is known in the literature as cointegration. In this particular case, x t and y t are said to be cointegrated. In our review of the development of the concept of cointegration, we identified that the underlying reason for this special case to arise is the proposition that if x t ~ I(d x ), y t ~ I(d y ), then z t = bx t + cy t ~ I(max(d x ,d y )). In this research, we offer evidence against this proposition.
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Notes
The knowledge that in response to the financial and economic crisis of 2007–2009, economists are open for re-evaluating alternative approaches to neoclassical paradigm gave us an additional strength to carry out this research (Neck 2014).
See Temin (2013) for an eloquent description of how or why economic history vanished both from the faculty and the graduate program at Massachusetts Institute of Technology (MIT), and subsequently its cost consequences to current economic education and overall societal scholarship.
Data files are available from the corresponding author upon request.
The anomalies that arise from the use of panel unit root tests are taken up separately.
According to the Bureau of Labor Statistics (BLS), which reports labor force statistics at the state level as well as at the federal level for the United States, labor force is the sum of employed and unemployed. It follows that the first difference of labor force is literally equal to the sum of the first difference of number of people employed and the first difference of number of people unemployed.
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Acknowledgments
The research was presented at the 85th Annual Meetings of the Southern Economic Association, November 21-23, 2015, New Orleans, USA and the 49th conference of the Canadian Economics Association during Thursday, May 28, 2015 - Sunday, May 31, 2015, in Toronto, Canada. We thank Afshin Amiraslany, Murshed Chowdhury, Brandon Mackinnon, Mariana Saenz and session participants in the above conferences for their helpful comments and suggestions. We also thank three anonymous referees for their comments and suggestions.
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Luitel, H.S., Mahar, G.J. Algebra of Integrated Time Series: Evidence from Unit Root Analysis. Int Adv Econ Res 22, 199–209 (2016). https://doi.org/10.1007/s11294-016-9577-9
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DOI: https://doi.org/10.1007/s11294-016-9577-9