Prof. Samuel Kobina Annim, Director of the African Centre for Statistics at the United Nations Economic Commission for Africa (UNECA), has revealed that the UN Population Division puts Ghana’s 2021 population about 1.6 million above the official census figure he oversaw.
He made the disclosure at the inaugural edition of the Academic Policy Dialogue Series organised by the Department of Data Science and Economic Policy at the University of Cape Coast (UCC).
Speaking to more than 100 participants on the theme “Building Pan-African Statistical System: The Stakes for the Academic and Policy Community,” the former Government Statistician argued that conflicting figures from national and international agencies weaken research, distort policy and erode public trust.
He urged African academics to stop treating data from the World Bank, the International Monetary Fund (IMF) and the United Nations as beyond question.
Ghana Population Figures Reveal a 1.6 Million Gap
Prof. Annim, who led the 2021 Population and Housing Census, said Ghana officially published its population as 30.8 million that year, while the UN Population Division’s estimate for the same year was about 1.6 million higher.
By 2024, he said, the difference between the two sources still stood at 1.4 million.
He noted that colleagues in the same school could run studies on population figures 1.6 million people apart, depending on which source they picked. “This is where I get out of the realm and I say that I’m not interested in 1%, 5% statistical significance. Here we are talking about human beings to the tune of 1.4 million, 1.6 million,” he said.
The problem is sharper elsewhere on the continent. Prof. Annim noted that eight African countries have gone two to four decades without a census, leaving governments without a reliable base for calculating GDP per capita or targeting social protection programmes.
He added that many countries do not realise that a revision of their population figures could move them from lower middle income to low income status.
Africa GDP Data Differs by Three Percentage Points
According to Prof. Annim, GDP estimates for some African countries differ by about three percentage points depending on the source consulted. He traced part of the gap to the way GDP is compiled in stages, moving from provisional to revised and final estimates over roughly two years, and to the IMF’s practice of revising its figures every April and October.
Other differences, he said, arise from local currency exchange rate conversions and from the different timing of revisions by national statistics offices and international agencies.
“Depending on when you source your data, revisions would have been done, and then you don’t get the same coefficient. You weaken the integrity among academics and then the trust from a policy side is compromised”.
Prof. Samuel Kobina Annim, Director of the African Centre for Statistics at the United Nations Economic Commission for Africa (UNECA)
Discussant Dr. Joshua Sebu extended the concern to business data. He compared the World Bank’s 2023 Enterprise Survey for Ghana, which he said recorded a 24.8 percent response rate and just 713 cases, with the Ghana Statistical Service’s much larger Integrated Business Establishment Survey.
“So the extension I would make is this national ownership should be accompanied by a transparent process for statistical reconciliation,” Dr. Sebu said.
Academics Urged to Question International Data Sources
Prof. Annim also turned the spotlight on his own profession. “Throughout my life in the classroom, I never had any editor questioning data that I’m getting from WDI. I never had any editor questioning data that is coming from the UN, or that is coming from the World Bank,” he said, referring to the World Bank’s World Development Indicators.
He cited American economist Steve Hanke’s public challenge to Ghana’s official inflation figures as a debate that Ghanaian academics should have led. Universities, he argued, need not confront global institutions directly, since documenting the discrepancies is itself a meaningful contribution.
Statistics Chiefs to Confront the Data Gaps
Prof. Annim said the African Centre for Statistics is now documenting the causes of such gaps across the continent. “We are not approaching any institution to say that your figure is wrong, this one is correct. All that we are doing is asking why there are differences and what could be the possible reasons for the differences,” he said.
He disclosed that the Centre will hold a lab session at the upcoming Statistical Commission for Africa, where heads of national statistics offices will be shown the discrepancies in their own figures and asked whether to resolve them.
The Department of Data Science and Economic Policy says it will turn the dialogue into a policy brief for policymakers in Ghana and across Africa.
