Due to the change in contractor and also the introduction of some methodological changes for estimating the South African population, these updates, which see the adult 15+ population growing by 2.7%, had a significant impact on the RAMS results.
The industry should examine these population changes carefully, bearing them in mind when dealing with changed audience results as there can be some trend-line breaks. These are particularly marked when using audience numbers (thousands) as opposed to share percentages.
Although the new universe update makes it difficult to establish which movements are due to the population changes and which are not, it is possible to see movements above and beyond those imposed by the new demographic model when users drill down into the data.
However, in general one can say that users can compare audiences across these breaks as the audiences were legitimately and correctly measured at each given point with the best possible measure at that time. Users must just be cautioned that they must do it while keeping the indicated changes in mind, and take care to establish whether significant audience shifts could have been due to the supplier change.
When looking at RAMS data for the past year, however, users cannot do a direct year-on-year comparison on cost per thousand as that could be misleading.
However, a period on period comparison from the May 2012 RAMS release onwards can be done. A period on period analysis can also be done for the period up to Feb 2012. By evaluating these trends in combination, real movements can be noted across the universe update. Should the levels leading up to February and after May be relatively stable, then any movement between these months is likely to be the result of the population changes.
SAARF has recently written an article on how to deal with the latest RAMS universe update, which can be found on the SAARF website under "RAMS".
