The National Bureau of Statistics (NBS) has clarified concerns over a projected spike in Nigeria’s December 2025 inflation figure, attributing it to technical base effects arising from the recent rebasing of the Consumer Price Index (CPI).
Speaking at a virtual stakeholder engagement organised by the NBS in collaboration with the Nigerian Economic Summit Group (NESG), the Statistician-General of the Federation, Adeyemi Adeniran, said the expected rise is linked to the adoption of 2024 as the new CPI base year, replacing 2009 after a 15-year gap.
Adeniran explained that the rebasing exercise, while necessary to reflect current consumption patterns, introduces arithmetic base effects that could temporarily inflate the year-on-year inflation rate when the December 2025 figure is released on January 15, 2026.
“Following the rebasing exercise and the methodology adopted for December 2025, a significant artificial spike in the inflation rate is expected,” he said, noting that December 2024 was set equal to 100 under the new series. He stressed that such base effects are common in index-based measurements and do not signal a deterioration in economic fundamentals.
He warned, however, that without clear communication, the technical spike could fuel uncertainty, undermine confidence in official statistics and complicate policy and business decisions. “When these effects are artificial rather than structural, it is essential to explain them clearly to users,” Adeniran said.
NESG Chief Executive Officer, Dr Tayo Aduloju, underscored the importance of credible inflation data as Nigeria transitions from economic stabilisation to consolidation, cautioning against mechanical reactions to headline figures during periods of reform.
“Inflation statistics must help us understand price dynamics properly, not just trigger alarm,” Aduloju said, warning that misleading signals could lead to costly policy errors at a sensitive stage of macroeconomic adjustment.
The Director of Price Statistics at the NBS, Dr Ayo Anthony, said the long gap since the last rebasing had significantly altered consumption patterns, leading to the inclusion of over 400 new products and the removal of more than 200 items from the CPI basket.
He explained that linking the new CPI series to the old one created unavoidable statistical complications, prompting the Bureau to adopt a normalisation process in line with the CPI Manual 2020. Under the adjustment, the average CPI for January to December 2024, rather than December alone, will be set equal to 100.
Anthony said the approach would remove the artificial base effect and present a more accurate picture of inflation dynamics, adding that the adjustment would have minimal impact on previously published data and would be fully disclosed.
He noted that the decision followed consultations with technical partners, including the International Monetary Fund, the World Bank and the Central Bank of Nigeria, and reaffirmed the NBS’s commitment to transparency and global best practice in statistical reporting.