Later today, the SA Reserve Bank's Monetary Policy Committee (MPC) will announce its decision on the rate at which the bank lends money to the commercial banking sector - the repo rate.
When the MPC meets, it has a large amount of data which can be used to assess the relationship between monetary policy and fiscal policy.
The MPC will know that in August, the year-on-year increase of headline inflation was 6.7 percent; consumer price inflation less mortgage costs (CPIX) was 6.3 percent; the producer price index (PPI) was 9.4 percent; economic growth for the second quarter, measured through gross domestic product, was 4.5 percent; and the official unemployment rate was 25.5 percent.
Of course, any policy-making body basing its decision on evidence will also consider trends and details, not just single figures.
For example, the headline inflation rate (year-on-year) was 0.3 percentage points lower than the 7 percent recorded in July.
The year-on-year increase in the CPIX for August was 0.2 percentage points lower than the 6.5 percent year-on-year increase recorded in July 2007.
The lower rate at August 2007 reflects decreases in the annual rates of change for non-alcoholic beverages - down to 3.6 percent in August 2007 from 4.5 percent in July 2007 - and the consumer price index's (CPI) annual rate for transport, which decreased to 1.4 percent in August from 4.2 percent in July.
At the same time, there were increases in the annual rates of change for food, which increased to 11.1 percent from 10.2 percent; milk, cheese and eggs, which increased to 16.5 percent from 14.1 percent; fats and oils, which increased to 17.4 percent from 15.5 percent; vegetables, which increased to 14.1 percent from 9.5 percent; and communication, which increased to 1.9 percent from 0.3 percent.
The main contributors to the annual increase of 6.7 percent in the CPI in August were food (2.4 percentage points), housing (2 percentage points), medical care and health expenses (0.5 percentage points), household operation (0.4 percentage points), education (0.4 percentage points) and fuel and power (0.3 percentage points).
As far as the PPI is concerned, the annual percentage change of 9.4 percent in August was 0.9 percent of a percentage point lower than the corresponding annual rate in July, when it was 10.3 percent. This lower annual rate in August reflected decreases in the annual rates of change in the PPI for a range of products, including electrical machinery and apparatus, metal products, products of petroleum and coal, and electricity.
In August, the annual percentage change in the PPI for locally produced commodities for consumption in South Africa was lower at 9.3 percent, while the rate of change in the PPI for imported commodities was higher at 9.7 percent.
Retail trade sales are an important indication of the demand for credit, the extension of which is generally viewed as inflationary.
The latest data on retail trade sales for the three months up to July, showed an increase of 6.8 percent compared with the three months up to July 2006.
Similarly, retail trade sales for the first seven months of 2007 increased by 8 percent compared with the first seven months of 2006. This is lower than the 9.5 percent growth for the first seven months of 2006 compared with the corresponding seven months of 2005.
Members of the MPC might wonder what has happened in respect of liquidations and insolvencies, which are themselves indicators of the demand for credit.
The number of liquidations recorded for the eight months ended August, decreased by 1.6 percent when compared with the eight months ended August 2006.
However, liquidations recorded for August increased by 16.2 percent when compared with August 2006.
Insolvencies recorded for the seven months ended July decreased by 21 percent compared with the seven months ended July 2006. The number of insolvencies recorded for July also decreased - by 22.6 percent - when compared with July 2006.
Civil cases for debt might also be considered when reviewing monetary policy.
In this case, civil summonses issued for debt for the three months ended July, decreased by 3.8 percent compared with the three months ended July 2006. In addition, the total number of civil judgments recorded for debt for the three months ended July, decreased by 2.4 percent compared with the three months ended July 2006.
While the total numbers decreased, the value of civil judgments for debt for the three months ended July increased by 2.3 percent compared with the three months ended July 2006. But year-on-year (July 2007 compared to July 2006), the total value of civil judgments for debt decreased by 5.7 percent.
The MPC might also consider the latest data on wholesale and motor trade sales; electricity generated and available for consumption; and the latest data on the manufacturing sector, which was released yesterday.
It has access to a wealth of data. This contrasts starkly with the situation in many other parts of the world, where absence of reliable and relevant data bedevils the efforts of policy makers to monitor and measure socio-economic trends, and determine policy on the basis of reliable and relevant evidence.