Some years back, users of official statistics raised a key question: how do the various data sets collected by Statistics SA relate to each other?
If cement production and sales are increasing, should this be reflected in statistics on construction Should an increase in manufacturing production be reflected in greater consumption of electricity?
There are factors that limit a one-to-one relation between data sets.
An increase in building plans passed would not immediately result in increased consumption of cement.
Greater consumption of electricity as a result of manufacturing production at the beginning of spring might not be apparent because of a decrease in domestic demand for heating.
However, these factors notwithstanding, data collections in different sectors should - over time - reflect a coherent picture of trends and developments.
Discontinuities in that expected coherence were one of the factors that alerted Stats SA to inadequacies in some of its statistical series.
This led to a major programme to address these weaknesses. Central to this were increased use of administrative records and development of a new business register from which to draw samples.
These are the core of a process of continuous improvement in the measurement of economic activity.
The economic data released this month paint a coherent picture of the economy, with statistics from different series generally reflecting similar trends.
During August, Stats SA published three trade-related statistical releases, namely wholesale, retail and motor trade. Wholesale trade sales at constant prices for the three months to May increased by 4.2 percent compared with the same period last year.
In addition, wholesale trade sales for the period January to May increased by 4.8 percent compared with the same period last year.
Retail trade sales at constant 2000 prices increased by 6.9 percent for March to May. Motor trade sales at current prices for May increased by 13 percent, while the growth for March to May was 20.2 percent.
In the area of manufacturing, production at constant prices for the three months to June increased by 3.9 percent and the seasonal adjustment estimates for the same period increased by 3.2 percent.
The latest published monthly survey for June on building statistics of the private sector, as reported by local government institutions, confirms the overall picture of increasing economic growth.
The preliminary estimates indicate that the value of recorded building plans passed by larger municipalities (at current prices) during the first six months of this year increased by 51.1 percent to R29.1 billion compared with the first six months of last year.
The value of buildings reported as completed to larger municipalities during the same period also increased substantially (41.6 percent to R12.3 billion).
These statistics are broadly consistent with Tuesday's release of gross domestic product (GDP) data for the second quarter of the year.
The seasonally adjusted real GDP at market prices for the second quarter compared with the first quarter increased by an annualised rate of 4.8 percent. This follows a growth rate of 3.5 percent for the first quarter.
The growth in the economy was broad-based, with none of the major divisions reporting negative growth. The strongest performance came from the manufacturing industry, which grew at an annualised rate of 7.3 percent in the second quarter, contributing 1.2 percentage points to overall growth.
Other main contributors to the increase were the wholesale and retail trade sector, the hotels and restaurants sector, and the finance, real estate and business services industry (0.7 percentage points each); transport, storage and communication (0.6 percentage points), and the agriculture, forestry and fishing industry and general government services and personal services (0.3 percentage points each).
Statistics collected by Stats SA in the various economic sectors paint a coherent and consistent picture of growth.
This suggests that the measurement of economic activity is improving as a result of the better coverage associated with the new business register. It also indicates that the continuous efforts to improve data quality are delivering good results.