Stats SA has defended the quality of the country’s latest census, saying concerns raised by scientists earlier this week are “unfounded and misleading”.
On Wednesday the Medical Research Council sounded the alarm about Census 2022, releasing a technical report that indicated it was so flawed that the government could not rely on it for resource allocation or monitoring key programmes.
Census 2022 had a 31% undercount, the biggest recorded to date by the UN Population Division. The undercount was not adequately corrected in the post-enumeration survey, said the report, compiled by leading UCT demographers Tom Moultrie and Rob Dorrington.
They said Stats SA’s 2022 population estimate of 62-million was 1-million people too high, and there were such material discrepancies at district and municipal level that the government could not rely on the data for budget allocations.
In response, Stats SA issued a statement on Thursday saying the accuracy of the numbers in Census 2022 had been validated by a review conducted by a group of local and international statistics experts, under the supervision of the Statistics Council.
“The council has assured both the minister in the presidency and the statistician-general that the Census 2022 data is indeed reliable,” it said.
Stats SA said it was dedicated to upholding standards of data accuracy, which were ensured by quality checks at every stage of the census process, from data collection to fieldwork monitoring. The post-enumeration survey helped detect and rectify any errors and ensured the reliability of the census data, it said.
A post-enumeration survey is a small-scale survey conducted after a census to identify who was and who was not counted in the census.
Moultrie and Dorrington said in their report that there were problems with the post-enumeration survey used to derive the adjustments that were made to produce the final population estimates. These include delays in running the post-enumeration survey, which should ideally be conducted within a month of the census, and running a post-enumeration survey that they said was too small to accurately adjust the enumerated population for the undercount.
Stats SA’s deputy director-general for population and social statistics, Solly Molai, said the process undertaken to identify and adjust for the missed population was statistically sound and in line with international best practice.
“The statistical procedure involves independently counting persons and households in two separate systems to identify overlap and estimate the true population size. The same method is used in all censuses,” he said.
Molai said Census 2022 had been extremely challenging to implement as it took place during the Covid-19 pandemic. The census was also affected by riots and local government elections, he said.
“The 2020 round of population census globally was a big challenge. We ensured adherence to best international practices and collaborated with other national statistics offices that were conducting a census in the same period,” he explained.
Stats SA said it had provided the report’s authors with comprehensive feedback to address the concerns they flagged. “It is disconcerting that the authors published their findings without acknowledging the valuable insights and responses provided by Stats SA,” it said.
“Our methodologies adhere to standards established by the UN, which are utilised by 99 countries worldwide ... the census figures for population and housing in 2022 are based on a foundation that will withstand scrutiny over time,” it said.
The MRC technical report said the census — which was originally planned for February 2021 but delayed to October 2022 — may have been rushed because the Treasury declined Stats SA’s request to roll over unspent funds from the 2021-22 fiscal year to the following year.
In response, Moloi said: “While this is a challenge, providing context is crucial. It is not as simple as the researcher pointed out. Stats SA and the Treasury worked together within the existing framework to ensure a successful count.”
The Treasury did not answer Business Day’s questions directly, but said in a brief written response to the publication on July 15 that it had no reason to doubt the quality of the census.
“However, we will engage Stat SA and the authors of the Medical Research Council report on their views, in order to assess the implications for the fiscal framework,” it said.
Updates: July 12 2024 and July 15 2024
This story was updated on July 12 to include additional comment by Stats SA’s deputy director-general for population and social statistics, Solly Moloi. It was updated again on July 15 to include reaction from Treasury.
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