South African Social Attitudes Survey 2011

The South African Social Attitudes Survey has been designed to yield a representative sample of adults aged 16 and older. The sampling frame used for the survey is based on the set of the 80787 enumerator areas (EAs) as were designed for the 2001 Population Census. Estimates of the population numbers for various categories of the census variables were obtained per EA. These estimates were annually updated to coincide with StatsSA's midyear estimates in respect of the variables province, gender, population group and age-group. In the updating of the 2007 version of this developed sampling frame, in addition to StatsSA's 2007 released midyear estimates, use was also made of (a) the GeoTerraImage (GTI) structure count in all metro EAs in 2004/2006 and (b) the ESKOM counts of dwelling units in all cities, towns, townships and villages.

After the release of the results of the 2007 Community Survey (the Community Survey indicated certain movements of the South African population), an intensive further update was performed making use of a large variety of variables for which data were available at the municipality level.

In all these created sampling frames special institutions (such as hospitals, military camps, old age homes, school and university hostels), recreational areas, industrial areas and vacant EAs were excluded prior to the drawing of the sample. In the sampling enumerator areas (EAs) were used as primary sampling units (PSUs) and the estimated number of dwelling units (taken as visiting point) in the EAs as secondary sampling units. In the first sampling stage PSUs (EAs) were drawn with probability proportional to size, using the estimated number of dwelling units (DUs) in an EA (PSU) as measure of size (MOS). The DU as secondary sampling unit has been defined as separate (non-vacant) residential stands, addresses, structures, flats, homesteads, etc.

In the second sampling stage a predetermined number of individual dwelling units (or visiting points) were drawn with equal probability in each of the drawn DUs.

Finally, in the third sampling stage a person was drawn with equal probability from all 16 year and older persons in the drawn DU. Three explicit stratification variables were used, namely province, geographic type and majority population group. Within each stratum, the allocated number of PSUs (which could differ between different strata) was drawn using proportional to size probability sampling with the estimated number of dwelling units in the PSU as measure of size (MOS).

In each of these drawn PSUs, two clusters of 7 dwelling units were drawn, thus resulting into two non-overlapping SASAS samples consisting of 7 DUs each.

Selection of individuals:

For each of the SASAS samples interviewers visited each visiting point drawn in the EA (PSU) and listed all eligible persons for inclusion in the sample, that is all persons currently aged 16 years or over and resident at the selected visiting point. The interviewer then selected one respondent using a random selection procedure based on a Kish grid.