Tuesday's release of the latest data on South Africa's gross domestic product (GDP) included estimates for the third quarter of this year, revised independent annual estimates for 2002 to 2004 and annual estimates of GDP by region up to 2004.
This release continued Statistics SA's practice of revising the quarterly estimates of GDP on an annual basis through the development of independent annual estimates of GDP within the supply and use framework.
This enables comparison of many data sources to ensure that estimates of value added and GDP are always as accurate as the existing data allow.
The availability of detailed annual and periodic data has allowed for more detailed and reliable estimates than were possible when the quarterly estimates were originally compiled.
Stats SA recently published the results of the economywide activity survey for last year and conducted periodic large sample surveys covering mining and quarrying, construction, accommodation and personal services.
In addition, the revision of basic statistics that feed into the compilation of GDP leads to the revision of the estimates for the relevant quarter and year. Basic data relating to agriculture, the government sector, financial intermediation and foreign trade were incorporated into the estimates.
Quarterly estimates of GDP are always of a preliminary nature and routinely subject to revision as more detailed annual and periodic data sets are incorporated. This is a common way of finding a balance between accuracy and timeliness, a dilemma faced by all official statistical agencies.
Publishing GDP estimates only once all the required data are available would render the estimates useless to stakeholders needing up-to-date and frequently published GDP data for planning and policy purposes. At the other extreme, publishing estimates that are hopelessly inaccurate because of the absence of appropriate data is equally futile.
Stats SA's solution - release of preliminary quarterly estimates, which are revised as and when more data become available - is a viable and sensible way of maintaining the required balance between accuracy and usefulness.
The estimates released earlier in the week show an economy growing at an seasonally adjusted and annualised rate of 4.2 percent in the third quarter of 2005, compared with the second quarter.
The main contributors to growth were manufacturing, the wholesale, retail, motor trade and hotels industries, and finance, real estate and business services. Each of these industries contributed 0.9 percentage points to growth.
The transport, storage and communication industries contributed 0.6 percentage points and the construction industry 0.3 percentage points.
The previously published annual GDP estimate for 2004 was a preliminary estimate, derived as the sum of the GDP of the four quarters of last year. Stats SA has now released revised annual and quarterly estimates of value added and GDP for 2004 as a result of the independent annual estimates.
This shows that the real growth rate for last year is 4.5 percent, revised from 3.7 percent. The main contributors to this growth were the finance, real estate and business services industries (1.4 percentage points), and the manufacturing and wholesale, retail, motor trade and hotels industries (0.8 percentage points each).
The latest data show that the economy is still dominated by the tertiary sector, which contributes 66.1 percent to the economy, with the primary sector contributing 10.1 percent and the secondary sector 23.8 percent.
The fastest-growing regional economy was that of the Western Cape (5.3 percent), followed by KwaZulu-Natal and the North West (4.9 percent).
Widespread debate over measurement of the economy preceded the release of these latest GDP estimates. Methodologically sound and routine revisions, based on the availability of additional data, have demonstrated that the South African economy is growing more rapidly than preliminary estimates suggested. This demonstrates the difference in approach between speculation and official statistics.