Approximating the DGP of China's quarterly GDP

We demonstrate that the Data Generating Process (DGP) of China's cumulated quarterly Gross Domestic Product (GDP, current prices), as it is reported by the National Bureau of Statistics of China (NBSC), can be (very closely) approximated by a simple rule. This rule says that the annual growth in any quarter is equal to the annual growth in its previous quarter plus an error term that is only nonzero in the first quarter of each year and with small variance. We show that this rule fits the data well for the period 1992Q1--2005Q4 for total GDP. It also gives accurate forecasts for 2006Q1--2009Q4.