Abstract
This paper contains results of the first part of a study in which a Vector Auto-Regression (VAR)/Vector Error Correction (VEC) model is developed and estimated to investigate dynamics of petroleum markets in OECD. Time series of the model comprises monthly data for the variables: demand for oil in OECD, WTI in real term as a benchmark oil price, industrial production in OECD as a proxy for income and commercial stocks of crude oil and oil products in OECD for the time period of January 1995 to March 2007. The detailed results of this empirical research are presented in different sections of the paper, nevertheless, the general result that emerges from this study could be summarized as follows: (i) There is convincing evidence of the series being non-stationary and integrated of order one I (1) with clear signs of co-integration relations between the series. (ii) The VAR system of the empirical study appears stable and restore its dynamics as usual following a shock to the rate of changes of different variables of the model taking between 5 to 8 periods (months in our case). (iii) It appears that the null hypothesis of ‘the expected mean of the series being insignificant from zero’, cannot be rejected in 5% level for each of four time-series indicating lack of statistical proof for presence of the deterministic trend in time-series of concern, (iv) Normality tests and histograms of the series reveals that while distribution of the samples in level differ from theoretical normal distribution however this is not the case for the differenced time series and for the residuals, on the other hand autocorrelation functions of the series are consistent with unit root process .(v) We find the lag length of 2 as being optimal for the estimated VAR model. (vi), Significant impact of changes in the commercial crude and products’ inventory level on oil price and on demand for oil is highlighted in our empirical study and in different formulations of the VAR model indicating importance of changes in stocks’ level on oil market dynamics. (vii) Income elasticity of demand for oil appear to be prominent and statistically significant in most estimated models of the VAR system, while price elasticity of demand for oil is found to be negligible and insignificant in the short-run.
Key terms: Petroleum market, Dynamics, OECD, VAR model, Stationary.
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