Statistics SA is to update its methodologies for determining the Consumer Price Index (CPI) and the Producer Price Index (PPI), Planning Commission Minister Trevor Manuel said on Tuesday.
He told the National Assembly during debate on his budget vote that StatsSA had to maintain the accuracy of the statistics being produced.
It was important that the data on which statistics were based was an accurate reflection of reality.
"For this reason, it needs to update its methodologies and surveys from time to time. A few years ago the Consumer Price Index (CPI) was radically overhauled."
The CPI was being improved through the usual periodic update of the basket of goods and services that were priced each month -- referred to as re-weighting -- as well as changing the reference period of the index -- known as rebasing.
The revised CPI would be released in February 2013. The revision was being done to ensure that the relative expenditure weights in the CPI reflected the changing behaviour of households and remained relevant and accurate.
The basket of items that formed part of the CPI was derived from the Income and Expenditure Survey, where a sample of 30,000 households were expected to maintain a diary of consumption for 12 months, Manuel said.
Similarly, the PPI was being re-engineered in a process that started in 2009. This would result in a parallel set of releases.
The PPI for manufacturing would be separated into two price indices. The first PPI, for manufacturing of goods for further processing, would include only goods which would be used again elsewhere in the manufacturing process, such as basic steel that would be used again in the manufacturing of motor vehicles.
The second PPI, for manufacturing of goods for final consumption, would include goods that were destined for final consumption, and included food items.
The PPI for final goods would track the CPI much more closely, since the items in the basket would be more similar than the current situation.
"So for example, an increase in fuel price will be reflected in both the manufacturing price index as well as in the agriculture price changes," Manuel said.
"The idea is to modernise the system so that price changes are tracked and reflected more accurately at the farm or factory gate."