Statistics can be collected through the application of different instruments. Questionnaires can be filled in by respondents, or information can be obtained from administrative records such as a population register, birth certificates, death notification forms or records of people leaving and entering a country.
These instruments are used to obtain information about a particular population: this could involve people (for example, medical doctors practising in a particular province); or businesses active in a particular economic sector (those involved in retail trade, or road transport, for example); or institutions (municipalities or hospitals).
When the agency gathering statistics covers the total population, this is known as a census; when only a part of the population is covered, this is a sample survey. Depending on the sample size, the methodology employed and the efficiency of information collection, sample surveys can provide highly reliable data. However, a full census (the enumeration of a total population) will invariably offer results of better quality than a sample survey.
Over the past decade, Statistics SA's household-based surveys, such as the general household survey and the labour force survey, have generally been based on a sample size of 30 000 households. This has been sufficient to provide information at a provincial level. The sample size of the economic surveys, on the other hand, varies greatly, depending on the number of business units operating in a given economic sector.
A household survey based on a far larger sample is being planned. The community survey, which goes to field in February 2007, is Stats SA's second-largest undertaking after the population census.
Under apartheid, racially defined population censuses were undertaken in 1951, 1960, 1970, 1980, 1985 and 1991, while inclusive national censuses were undertaken in 1996 and 2001. Only the last two were able to provide reliable data at a municipal level.
In March 2004, following advice from the Statistics Council, the cabinet resolved that the sort of population and housing censuses conducted in 1996 and 2001 would be carried out in a 10-year cycle and scheduled the next census for 2011. However, to ensure regular updates on major trends in social data, reported on at appropriate geographical levels (including municipalities), the cabinet also proposed the introduction of an extended annual household survey. This is what is now known as the community survey.
Stats SA undertook extensive consultation to determine the information stakeholders expected as an outcome of the community survey. Ten stakeholder workshops were held across the country during August and September 2004. About 367 stakeholders, predominantly from national, provincial and local government departments, as well as from research and educational institutions, attended.
The survey will record key demographic information; details of disability, fertility and mortality; migration; education; involvement in public works programmes; economic activity, including employment and unemployment; and access to housing and services such as sanitation, water, energy and refuse removal.
The community survey is the largest sample survey undertaken by Stats SA. It will be based on a sample of 280 000 households, compared with the 30 000 sampled in previous household surveys.
The community survey is a massive undertaking. The logistics and planning required are considerable. However, the expected outcome - key social data for the country as a whole, provinces and municipalities - is essential to monitor and measure changes to and developments in South Africa's social structure.