kjedeindeks

A kjedeindeks, or chain index in English, is a statistical tool used to measure changes in a variable over time, especially when the underlying structure or definition of the variable changes. It is particularly useful for economic indicators like inflation or unemployment.

The core idea of a kjedeindeks is to overcome the limitations of a fixed-base index. In a fixed-base index, the reference year remains constant, which can lead to distortions if the composition of goods and services or the way they are measured changes significantly over time. A kjedeindeks addresses this by periodically re-basing the index to a more recent period.

This re-basing process involves linking together indices calculated for different periods. For example, an inflation index might be calculated for 2010-2015 using one basket of goods, and then for 2016-2020 using an updated basket. The kjedeindeks connects these separate indices to create a continuous time series.

The advantage of this method is that it better reflects current consumption patterns and economic realities, providing a more accurate picture of inflation or other trends. However, it can make direct comparisons between very distant points in time more complex, as the underlying reference baskets may have differed. Statistical agencies often provide both fixed-base and chained indices to offer different perspectives on long-term trends.