Export and import unit value indices
Highlights
- Stats SA will introduce a new Export and import unit value index (UVI) to replace the current Export and import price indices.
- The UVI series will be based on customs data from SARS and includes a much wider span of international trade transactions than is possible with the historic price index.
- The new index should be more responsive to changes in trade conditions, including currency fluctuations, than the price index.
- The new index will be published two months after the reference month. This means that the January 2014 edition will be published in March.
Introduction
Stats SA currently publishes price indices for exports and imports. These price indices are used mainly for the purpose of deflating trade and national accounts data. Economists also use them to analyse the impact of currency changes or other international factors on prices.
Advantages of a Unit Value Index
As the same products are not usually imported or exported every month, it makes traditional surveying of prices of these commodities challenging. This is particularly true for certain important categories such as machinery and equipment where the composition of trade varies significantly from month to month. Consequently, certain components of the current series do not show much movement from month to month.
Many countries publish a Unit Value Index to avoid this problem. UVIs are derived from customs data recorded from actual imports and exports. The South African Revenue Service (SARS) provides these data to Stats SA each month following the publication of the trade data.
The products comprising the index and their respective weights are based on the total value of imports and exports in the previous year. The weights will be updated annually in January. The indices are calculated by dividing trade values by corresponding trade quantities to obtain implied prices (unit values) every month.
Publication details
The official indices will be shown from 2013. The UVIs will be published monthly, but with a two-month lag (the data are received at the beginning of the second month). The UVIs will be released on the same day as the PPI release – the last Thursday of the month. A mockup of the publication format will be made available before the first release.
Because the composition and value of exports and imports can be highly volatile, the export UVI series will use a three month moving average and the import series a five month moving average.
Users will be provided with an analytical time series starting in January 2010. It should be noted that the data prior to 2012 are less reliable and comparable because of the improvements to the administrative data sources. While they are indicative, they should be used with caution. Stats SA does not advise linking the UVIs with the old price series as they are not comparable.
Stats SA will provide a methods and sources manual for the UVIs which will be available at www.statssa.gov.za.
For further enquiries:
Patrick Kelly, Executive manager: Price statistics
Tel: 012 310 8290
E-mail: Patrickke@statssa.gov.za
Marais Kleu
Manager: Producer price index
Tel: 012 310 8170
Email: Maraisk@statssa.gov.za
