The Paasche index is a statistical tool created by the German economist Hermann Pasche that is used to track changes in price and quantity over time. Unlike other methods, its calculations are fixed to the present moment. This is why it differs from the Laspeyres index, which is based on historical data.
To understand how it works, look at the math. This index calculates the total cost of a certain combination of goods at current prices. This number is then compared to the price of the same package in the base-period. Multiply this ratio by 100 to get the final figure.
The Paasche price index takes into account changes in consumption habits and therefore tends to underestimate price increases.
This distinction is important. When prices rise, consumers often change their habits. They might buy less of an expensive item and cheaper alternatives. Paasche index noticed this reaction immediately. It uses current-period weighting. This means that it reflects the reality of what people are actually buying today.
The result is a small deviation. This index often underestimates actual inflation. Why? This is because consumer reaction to high costs has already been taken into account. The index considers a drop in consumption when people stop buying expensive goods a sign that prices are relatively stable. It does not penalize buyers for adapting.
This approach provides a snapshot of the current economic situation. Instead of predicting future trends, we measure the direct effect of price changes on current consumption habits.
