Inflation is a crucial economic indicator, but the Consumer Price Index (CPI)—its primary measurement tool—can sometimes fail to capture the full extent of rising prices. This disconnect occurs because the CPI reflects a fixed basket of goods and services that may not account for all shifts in consumption patterns or hidden price pressures.
For example, Kenya’s CPI in December 2024 reported a year-on-year inflation rate of 3.0%. While this figure suggested moderate inflation, it overlooked significant cost increases in areas that may not be fully represented in the index. Food and non-alcoholic beverages, which recorded a 4.8% annual rise, heavily influenced the CPI. However, the housing, water, electricity, and gas category, despite its substantial 14.6% weight, experienced a 0.2% decline, offsetting the overall inflation rate.
This can lead to underestimating inflation. As households shift spending from cheaper to more expensive alternatives due to shortages or quality declines, the CPI’s fixed basket fails to reflect these changes. For instance, while maize flour prices surged by 7.0% in December 2024, some consumers may have switched to more expensive substitutes or reduced consumption altogether. Similarly, seasonal spikes in matatu fares, up 50.0% on some routes, may not fully represent the broader transport cost burdens.
Another factor is quality adjustments. The CPI often accounts for quality improvements by assuming consumers receive more value for the same price. Yet, this can mask price increases if consumers do not perceive these improvements as meaningful. For example, while kerosene prices fell by 2.0% monthly, this may not offset other rising energy costs that weigh on households.
Additionally, new products and services entering the market may drive up costs without being included in the CPI basket until later revisions. This delay creates a lag in capturing inflation dynamics.
Policymakers relying solely on the CPI risk underestimating inflation’s real impact. Broader measures, such as tracking expenditure shares or supplemental indices, can help bridge this gap. Without these, rising costs in essential sectors could erode purchasing power without appearing in headline inflation figures.
While the CPI is a valuable tool, it is not infallible. Hidden inflation underscores the need for more nuanced measurements to ensure economic policies address the realities faced by households.
