The "base effect" refers to the influence of the price levels from the previous year on the current calculation of inflation rates. When prices are low in the prior year, any subsequent increase may produce a disproportionately high inflation rate, as the percentage change is calculated against a smaller base. This concept is crucial for understanding economic indicators, as it highlights the potential for distorted perceptions of economic health due to the selection of the base period, emphasizing the need for careful analysis of inflation trends over time.