The National Bureau of Statistics (NBS) says it will publish two separate inflation figures for December after changes to its consumer price index (CPI) methodology caused the headline rate to more than double.
This is according to information reported by Bloomberg, citing comments from the statistics agency on Monday.
The development follows the recent rebasing of Nigeria’s CPI, which introduced methodological adjustments that significantly distorted the December inflation reading.
The inflation data, scheduled for release on January 15, are projected to show an “artificially spiked” inflation rate of 31.2% for December, compared with 14.5% recorded in November.
What NBS is saying
The Statistician-General of the Federation, Prince Adeyemi Adeniran, said the agency will take the unusual step of publishing both inflation figures to ensure transparency. According to him, one figure will reflect economic fundamentals, while the other will capture the inflated outcome resulting from the rebasing methodology.
Ayo Andrew, Head of Price Statistics at the NBS, also disclosed that the agency may revise its monthly inflation figures to address the distortions caused by the methodological changes. He explained that the problem arose largely from how the new base period was computed.
“The lesson is to have timely rebasing to avoid such errors,” Adeniran said, adding that the artificial spike does not reflect the “economic fundamentals but arithmetic issues.”
“It is not something unexpected, it is not something unusual. Base effects are common,” he said.
According to Andrew, the long delay in updating the CPI basket and the large number of items added contributed significantly to the methodological distortion seen in the December figure.
Context
In 2024, the NBS rebased Nigeria’s consumer price index for the first time in 16 years, shifting the reference year to 2024.
Unlike previous rebasing exercises that used a single month as the base period, the agency calculated the base using the average of all months in 2024.
The rebasing also involved reweighting several categories and expanding the inflation basket to 934 items from 740.
Why this matter
Inflation data play a critical role in economic planning, monetary policy, and investor decision-making.
A sudden jump in the headline inflation rate, even if artificial, could distort public perception and policy responses if not properly explained.
Adeniran emphasized that the spike does not reflect Nigeria’s economic fundamentals but is driven by arithmetic and base effects.
He noted that such base effects are not unusual in statistical computations, stressing that more frequent and timely rebasing would help prevent similar issues in the future.
What you should know
Nigeria’s inflation data are closely monitored by the Central Bank of Nigeria (CBN) as it transitions toward an inflation-targeting monetary policy framework.
The CBN has already factored in the CPI rebasing and related computational issues in its three-year inflation forecast.
The apex bank is targeting a slowdown in inflation to around 13% by next year, despite current price pressures and statistical adjustments.
