Nigeria's CPI Rebasing in 2024: What the New Inflation Numbers Actually Mean

When the National Bureau of Statistics (NBS) published its January 2024 Consumer Price Index report, the headline figure dropped from 29.90% to 24.48% overnight. No policy had changed. No prices had fallen. The naira had not recovered. What happened was a technical operation called a CPI rebasing — and understanding it is essential for any Nigerian trying to read inflation data with clear eyes.

What Is CPI Rebasing and Why Did NBS Do It in 2024?

The Consumer Price Index measures how much the average Nigerian household pays for a fixed basket of goods and services over time. That basket — and the weights assigned to each item inside it — is set during a base-year survey. Nigeria's previous base year was 2009, meaning the NBS had been tracking price changes against a consumption pattern that was fifteen years old.

A 2009 basket did not reflect a 2024 economy. It under-weighted mobile data, food delivery, and urban transport costs that had become significant household expenditures. It also over-weighted categories that had shrunk in real-life spending. The result was a CPI that was increasingly disconnected from lived experience.

The NBS shifted the base year to 2024/2025, anchoring the index to a fresh National Living Standards Survey. This involved two concrete changes. First, the basket composition was updated to reflect actual current spending patterns across urban and rural Nigeria. Second, the reference period for the index was reset to 100, which mechanically resets percentage-change readings.

The immediate statistical effect was a lower headline number. In January 2024 — the first month published under the new methodology — all-items CPI came in at 24.48% year-on-year under the rebased series, compared to 29.90% that the old series would have recorded for the same calendar month. Food inflation, which had been running above 35% on the old measure, was repriced to approximately 26.08%.

Does a Lower CPI Number Mean Nigerians Are Actually Better Off?

The short answer is no. The NBS itself was explicit: rebasing is a methodological update, not a measure of economic improvement.

To understand why, consider what actually happened to prices between 2023 and early 2024. The naira's managed float, de facto devalued in June 2023 following the CBN's unification of the official and parallel market rates, collapsed the exchange rate from roughly ₦460 per dollar to above ₦1,500 per dollar by early 2024. The parallel market, tracked by platforms including Nairametrics and the NAFEM window data published by the CBN, showed the naira breaching ₦1,580 per dollar in February 2024.

Import costs — which feed directly into food prices, fuel costs, and manufactured goods — surged accordingly. The NBS food price survey, published monthly, recorded tomatoes, rice, and palm oil all posting double-digit monthly gains through the second half of 2023. Garri (white, sold per kg) rose from ₦382 in January 2023 to above ₦900 in January 2024 in multiple state surveys.

So what the rebasing did was correct a measurement distortion, not reverse any of these pressures. The new basket acknowledges that Nigerians now spend a larger share of income on certain categories; the weights assigned to those categories reflect that reality. In some cases, this actually made the index more sensitive to food shocks, not less.

The IMF, in its 2024 Article IV consultation with Nigeria, noted that while the rebasing represented a statistical improvement, underlying inflationary pressures remained elevated. The Fund projected average CPI inflation for 2024 in excess of 20% even under the new methodology, contingent on fuel subsidy removal effects fully passing through to transport and food logistics costs.

How the New Basket Weights Changed the Numbers

The 2024 rebase restructured the major divisions of the CPI. Under the old 2009 series, food and non-alcoholic beverages carried a weight of approximately 51.8%. The updated basket, reflecting shifts in household expenditure from the 2022/23 National Living Standards Survey, adjusted this weight downward modestly while increasing the share assigned to housing, water, electricity, and transport.

This matters because food inflation in Nigeria has consistently outpaced core (non-food) inflation since 2022. Lowering food's basket weight mechanically dampens the composite headline figure, even if food prices themselves continue rising at the same pace.

Transport costs — sensitive to petrol prices following the May 2023 fuel subsidy removal by the Tinubu administration — were also given higher weighting in the updated basket, partially offsetting the food weight reduction.

The NBS also introduced a broader geographic coverage, adding price data from additional states that were underrepresented in the 2009 survey. This improved the CPI's representativeness for rural consumers, who face structurally different price dynamics from Lagos or Abuja households.

What Investors and Savers Should Actually Watch

For individuals managing savings or monitoring the real return on assets, the rebasing creates a practical challenge: the old and new CPI series are not directly comparable. A year-on-year figure published in March 2025 is computed against the March 2024 base-period reading, which was itself a rebased number. This creates a clean run of comparable data from January 2024 onwards, but comparisons to 2022 or 2023 highs require a conversion table that the NBS published alongside the rebasing announcement.

The NGX (Nigerian Exchange Group) tracks real equity returns partly against CPI. Fixed-income investors monitoring Treasury Bill yields, which the CBN Debt Management Office (DMO) publishes at each primary market auction, should note that a headline CPI of 24–26% implies deeply negative real returns on instruments yielding below that rate. As of Q1 2024, 91-day T-Bills were auctioned at stop rates ranging from 17% to 21%, well below the rebased CPI.

For context on what inflation does to naira-denominated savings over time, the parent guide What Is Inflation in Nigeria: NBS, CPI and How It Affects You explains the mechanics in detail.

The NBS Credibility Question

The rebasing prompted a wave of commentary, some of it sceptical. Critics argued that the timing — releasing a lower number during a period of acute cost-of-living pressure — served political interests. The NBS rejected this, noting that rebasings are routine statistical exercises recommended by the United Nations Statistics Division and that Nigeria was long overdue for one, given that a 2009 base year had survived multiple economic cycles and was widely acknowledged as obsolete by statisticians.

International precedent supports the NBS position. The UK's Office for National Statistics rebases its CPI basket annually. Kenya rebased its CPI in 2019. South Africa completed a major basket revision in 2022. In each case, the rebasing produced methodologically better data without implying any price decrease.

The more legitimate concern is whether the NBS has the resources and independence to conduct these exercises rigorously. The Bureau's funding, staff capacity, and the quality controls around its price-collection fieldwork remain areas of ongoing discussion in Nigeria's data-quality debates.

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Regulatory note: The Central Bank of Nigeria (CBN) sets monetary policy in response to NBS CPI data under its price stability mandate; the current Monetary Policy Rate (MPR) stands at 26.25% as of May 2024, reflecting the CBN's tightening cycle. The Federal Inland Revenue Service (FIRS) uses inflation-adjusted figures for certain tax threshold calculations. The Securities and Exchange Commission (SEC) requires that fund managers disclose real return projections net of current CPI. The Cowrie is an independent editorial publication. We do not hold a financial services licence and nothing in this article constitutes investment advice or a solicitation to buy or sell any financial product.