In this paper, the sales of vehicles in the US are examined to understand if the shock caused by the current COVID-19 pandemic has had permanent or transitory effects on its subsequent evolution. Using monthly data from January 1976 until April 2021 and fractional integration methods, our results indicate that the series reverts and the shocks tend to disappear in the long run, even when they appear to be long lived. The results also indicate that the COVID-19 pandemic has not increased the degree of persistence of the series but, unexpectedly, has slightly reduced its dependence. Thus, shocks are transitory, long lived but, as time goes by, the recovery seems to be faster, which is possibly a sign of the strength of the industry.

This paper analyses the persistence of research intensity in the OECD over the period 1870-2018. The goal is to test if the conclusion of the study conducted by Ang and Madsen (Ang, J. B., & Madsen, J. B. (2011). Can second-generation endogenous growth models explain the productivity trends and knowledge production in the Asian miracle economies? The Review of Economics and Statistics 2011, 93(4), 1360-1373), namely that the Schumpeterian growth models predict that research intensity is stationary, is correct. Using fractional integration methods on annual research intensity from 16OECD countries, we observe that the series are very persistent. The order of integration is observed to be statistically higher than 1 in all the countries except Spain, rejecting thus the hypothesis of stationarity.When the likelihood of non-linear trends is considered in the analysis, the results are not materially different. An implication of the results is that policies aimed at boosting research activities will have a long-term impact on research intensity.